java.lang.Object
- org.apache.flink.table.api.internal.BaseExpressions<InType,OutType>

Type Parameters:

InType - The accepted type of input expressions, it is Expression for Scala and Object for Java. Generally the expression DSL works on expressions, the reason why Java accepts Object is to remove cumbersome call to lit() for literals. Scala alleviates this problem via implicit conversions.

OutType - The produced type of the DSL. It is ApiExpression for Java and Expression for Scala. In Scala the infix operations are included via implicit conversions. In Java we introduced a wrapper that enables the operations without pulling them through the whole stack.

Direct Known Subclasses:

ApiExpression
```
@PublicEvolving
public abstract class BaseExpressions<InType,OutType>
extends Object
```
These are Java and Scala common operations that can be used to construct an Expression AST for expression operations.

Constructor Summary

Constructors
Constructor Description

BaseExpressions()

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods Deprecated Methods
Modifier and Type	Method	Description
`OutType`	`abs()`	Calculates the absolute value of given value.
`OutType`	`acos()`	Calculates the arc cosine of a given number.
`OutType`	`and(InType other)`	Boolean AND in three-valued logic.
`OutType`	`arrayConcat(InType... arrays)`	Returns an array that is the result of concatenating at least one array.
`OutType`	`arrayContains(InType needle)`	Returns whether the given element exists in an array.
`OutType`	`arrayDistinct()`	Returns an array with unique elements.
`OutType`	`arrayMax()`	Returns the maximum value from the array.
`OutType`	`arrayMin()`	Returns the minimum value from the array.
`OutType`	`arrayPosition(InType needle)`	Returns the position of the first occurrence of element in the given array as int.
`OutType`	`arrayRemove(InType needle)`	Removes all elements that equal to element from array.
`OutType`	`arrayReverse()`	Returns an array in reverse order.
`OutType`	`arraySlice(InType startOffset)`
`OutType`	`arraySlice(InType startOffset, InType endOffset)`	Returns a subarray of the input array between 'start_offset' and 'end_offset' inclusive.
`OutType`	`arrayUnion(InType array)`	Returns an array of the elements in the union of array1 and array2, without duplicates.
`OutType`	`as(String name, String... extraNames)`	Specifies a name for an expression i.e.
`OutType`	`asc()`	Specifies ascending order of an expression i.e.
`OutType`	`ascii()`	Returns the numeric value of the first character of the input string.
`OutType`	`asin()`	Calculates the arc sine of a given number.
`OutType`	`at(InType index)`	Accesses the element of an array or map based on a key or an index (starting at 1).
`OutType`	`atan()`	Calculates the arc tangent of a given number.
`OutType`	`avg()`	Returns the average (arithmetic mean) of the numeric field across all input values.
`OutType`	`between(InType lowerBound, InType upperBound)`	Returns true if the given expression is between lowerBound and upperBound (both inclusive).
`OutType`	`bin()`	Returns a string representation of an integer numeric value in binary format.
`OutType`	`cardinality()`	Returns the number of elements of an array or number of entries of a map.
`OutType`	`cast(org.apache.flink.api.common.typeinfo.TypeInformation<?> toType)`	Deprecated. This method will be removed in future versions as it uses the old type system.
`OutType`	`cast(org.apache.flink.table.types.DataType toType)`	Returns a new value being cast to `toType`.
`OutType`	`ceil()`	Calculates the smallest integer greater than or equal to a given number.
`OutType`	`ceil(org.apache.flink.table.expressions.TimeIntervalUnit timeIntervalUnit)`	Rounds up a time point to the given unit.
`OutType`	`charLength()`	Returns the length of a string.
`OutType`	`chr()`	Returns the ASCII character result of the input integer.
`OutType`	`collect()`	Returns multiset aggregate of a given expression.
`OutType`	`cos()`	Calculates the cosine of a given number.
`OutType`	`cosh()`	Calculates the hyperbolic cosine of a given value.
`OutType`	`cot()`	Calculates the cotangent of a given number.
`OutType`	`count()`	Returns the number of input rows for which the field is not null.
`OutType`	`day()`	Creates an interval of the given number of days.
`OutType`	`days()`	Creates an interval of the given number of days.
`OutType`	`decode(InType charset)`	Decodes the first argument into a String using the provided character set.
`OutType`	`degrees()`	Converts numeric from radians to degrees.
`OutType`	`desc()`	Specifies descending order of an expression i.e.
`OutType`	`distinct()`	Similar to a SQL distinct aggregation clause such as COUNT(DISTINCT a), declares that an aggregation function is only applied on distinct input values.
`OutType`	`dividedBy(InType other)`	Returns left divided by right.
`OutType`	`element()`	Returns the sole element of an array with a single element.
`OutType`	`encode(InType charset)`	Encodes the string into a BINARY using the provided character set.
`OutType`	`end()`	Returns the end time (exclusive) of a window when applied on a window reference.
`OutType`	`exp()`	Calculates the Euler's number raised to the given power.
`OutType`	`extract(org.apache.flink.table.expressions.TimeIntervalUnit timeIntervalUnit)`	Extracts parts of a time point or time interval.
`OutType`	`firstValue()`	Returns the first value of field across all input values.
`OutType`	`flatten()`	Converts a Flink composite type (such as Tuple, POJO, etc.) and all of its direct subtypes into a flat representation where every subtype is a separate field.
`OutType`	`floor()`	Calculates the largest integer less than or equal to a given number.
`OutType`	`floor(org.apache.flink.table.expressions.TimeIntervalUnit timeIntervalUnit)`	Rounds down a time point to the given unit.
`OutType`	`fromBase64()`	Returns the base string decoded with base64.
`OutType`	`get(int index)`	Accesses the field of a Flink composite type (such as Tuple, POJO, etc.) by index and returns it's value.
`OutType`	`get(String name)`	Accesses the field of a Flink composite type (such as Tuple, POJO, etc.) by name and returns it's value.
`OutType`	`hex()`	Returns a string representation of an integer numeric value or a string in hex format.
`OutType`	`hour()`	Creates an interval of the given number of hours.
`OutType`	`hours()`	Creates an interval of the given number of hours.
`OutType`	`ifNull(InType nullReplacement)`	Returns `nullReplacement` if the given expression is NULL; otherwise the expression is returned.
`OutType`	`in(InType... elements)`	Returns true if an expression exists in a given list of expressions.
`OutType`	`in(Table table)`	Returns true if an expression exists in a given table sub-query.
`OutType`	`initCap()`	Converts the initial letter of each word in a string to uppercase.
`OutType`	`instr(InType str)`	Returns the position of the first occurrence of the input string.
`OutType`	`isEqual(InType other)`	Equals.
`OutType`	`isFalse()`	Returns true if given boolean expression is false.
`OutType`	`isGreater(InType other)`	Greater than.
`OutType`	`isGreaterOrEqual(InType other)`	Greater than or equal.
`OutType`	`isJson()`	Determine whether a given string is valid JSON.
`OutType`	`isJson(org.apache.flink.table.api.JsonType type)`	Determine whether a given string is valid JSON.
`OutType`	`isLess(InType other)`	Less than.
`OutType`	`isLessOrEqual(InType other)`	Less than or equal.
`OutType`	`isNotEqual(InType other)`	Not equal.
`OutType`	`isNotFalse()`	Returns true if given boolean expression is not false (for null and true).
`OutType`	`isNotNull()`	Returns true if the given expression is not null.
`OutType`	`isNotTrue()`	Returns true if given boolean expression is not true (for null and false).
`OutType`	`isNull()`	Returns true if the given expression is null.
`OutType`	`isTrue()`	Returns true if given boolean expression is true.
`OutType`	`jsonExists(String path)`	Determines whether a JSON string satisfies a given search criterion.
`OutType`	`jsonExists(String path, org.apache.flink.table.api.JsonExistsOnError onError)`	Returns whether a JSON string satisfies a given search criterion.
`OutType`	`jsonQuery(String path)`	Extracts JSON values from a JSON string.
`OutType`	`jsonQuery(String path, org.apache.flink.table.api.JsonQueryWrapper wrappingBehavior)`	Extracts JSON values from a JSON string.
`OutType`	`jsonQuery(String path, org.apache.flink.table.api.JsonQueryWrapper wrappingBehavior, org.apache.flink.table.api.JsonQueryOnEmptyOrError onEmpty, org.apache.flink.table.api.JsonQueryOnEmptyOrError onError)`	Extracts JSON values from a JSON string.
`OutType`	`jsonValue(String path)`	Extracts a scalar from a JSON string.
`OutType`	`jsonValue(String path, org.apache.flink.table.types.DataType returningType)`	Extracts a scalar from a JSON string.
`OutType`	`jsonValue(String path, org.apache.flink.table.types.DataType returningType, InType defaultOnEmptyOrError)`	Extracts a scalar from a JSON string.
`OutType`	`jsonValue(String path, org.apache.flink.table.types.DataType returningType, org.apache.flink.table.api.JsonValueOnEmptyOrError onEmpty, InType defaultOnEmpty, org.apache.flink.table.api.JsonValueOnEmptyOrError onError, InType defaultOnError)`	Extracts a scalar from a JSON string.
`OutType`	`lastValue()`	Returns the last value of field across all input values.
`OutType`	`left(InType len)`	Returns the leftmost integer characters from the input string.
`OutType`	`like(InType pattern)`	Returns true, if a string matches the specified LIKE pattern.
`OutType`	`listAgg()`	Concatenates the values of string expressions and places separator(,) values between them.
`OutType`	`listAgg(String separator)`	Concatenates the values of string expressions and places separator values between them.
`OutType`	`ln()`	Calculates the natural logarithm of the given value.
`OutType`	`locate(InType str)`	Returns the position of the first occurrence in the input string.
`OutType`	`locate(InType str, InType pos)`	Returns the position of the first occurrence in the input string after position integer.
`OutType`	`log()`	Calculates the natural logarithm of the given value.
`OutType`	`log(InType base)`	Calculates the logarithm of the given value to the given base.
`OutType`	`log10()`	Calculates the base 10 logarithm of the given value.
`OutType`	`log2()`	Calculates the base 2 logarithm of the given value.
`OutType`	`lowerCase()`	Returns all of the characters in a string in lower case using the rules of the default locale.
`OutType`	`lpad(InType len, InType pad)`	Returns a string left-padded with the given pad string to a length of len characters.
`OutType`	`ltrim()`	Returns a string that removes the left whitespaces from the given string.
`OutType`	`mapEntries()`	Returns an array of all entries in the given map.
`OutType`	`mapKeys()`	Returns the keys of the map as an array.
`OutType`	`mapValues()`	Returns the values of the map as an array.
`OutType`	`max()`	Returns the maximum value of field across all input values.
`OutType`	`md5()`	Returns the MD5 hash of the string argument; null if string is null.
`OutType`	`milli()`	Creates an interval of the given number of milliseconds.
`OutType`	`millis()`	Creates an interval of the given number of milliseconds.
`OutType`	`min()`	Returns the minimum value of field across all input values.
`OutType`	`minus(InType other)`	Returns left minus right.
`OutType`	`minute()`	Creates an interval of the given number of minutes.
`OutType`	`minutes()`	Creates an interval of the given number of minutes.
`OutType`	`mod(InType other)`	Calculates the remainder of division the given number by another one.
`OutType`	`month()`	Creates an interval of the given number of months.
`OutType`	`months()`	Creates an interval of the given number of months.
`OutType`	`not()`	Inverts a given boolean expression.
`OutType`	`notBetween(InType lowerBound, InType upperBound)`	Returns true if the given expression is not between lowerBound and upperBound (both inclusive).
`OutType`	`or(InType other)`	Boolean OR in three-valued logic.
`OutType`	`over(InType alias)`	Defines an aggregation to be used for a previously specified over window.
`OutType`	`overlay(InType newString, InType starting)`	Replaces a substring of string with a string starting at a position (starting at 1).
`OutType`	`overlay(InType newString, InType starting, InType length)`	Replaces a substring of string with a string starting at a position (starting at 1).
`OutType`	`parseUrl(InType partToExtract)`	Parse url and return various parameter of the URL.
`OutType`	`parseUrl(InType partToExtract, InType key)`	Parse url and return various parameter of the URL.
`OutType`	`plus(InType other)`	Returns left plus right.
`OutType`	`position(InType haystack)`	Returns the position of string in an other string starting at 1.
`OutType`	`power(InType other)`	Calculates the given number raised to the power of the other value.
`OutType`	`proctime()`	Declares a field as the proctime attribute for indicating, accessing, and working in Flink's processing time.
`OutType`	`quarter()`	Creates an interval of the given number of quarters.
`OutType`	`quarters()`	Creates an interval of the given number of quarters.
`OutType`	`radians()`	Converts numeric from degrees to radians.
`OutType`	`regexp(InType regex)`	Returns TRUE if any (possibly empty) substring matches the Java regular expression, otherwise FALSE.
`OutType`	`regexpExtract(InType regex)`	Returns a string extracted with a specified regular expression.
`OutType`	`regexpExtract(InType regex, InType extractIndex)`	Returns a string extracted with a specified regular expression and a regex match group index.
`OutType`	`regexpReplace(InType regex, InType replacement)`	Returns a string with all substrings that match the regular expression consecutively being replaced.
`OutType`	`repeat(InType n)`	Returns a string that repeats the base string n times.
`OutType`	`replace(InType search, InType replacement)`	Returns a new string which replaces all the occurrences of the search target with the replacement string (non-overlapping).
`OutType`	`reverse()`	Reverse each character in current string.
`OutType`	`right(InType len)`	Returns the rightmost integer characters from the input string.
`OutType`	`round(InType places)`	Rounds the given number to integer places right to the decimal point.
`OutType`	`rowtime()`	Declares a field as the rowtime attribute for indicating, accessing, and working in Flink's event time.
`OutType`	`rpad(InType len, InType pad)`	Returns a string right-padded with the given pad string to a length of len characters.
`OutType`	`rtrim()`	Returns a string that removes the right whitespaces from the given string.
`OutType`	`second()`	Creates an interval of the given number of seconds.
`OutType`	`seconds()`	Creates an interval of the given number of seconds.
`OutType`	`sha1()`	Returns the SHA-1 hash of the string argument; null if string is null.
`OutType`	`sha2(InType hashLength)`	Returns the hash for the given string expression using the SHA-2 family of hash functions (SHA-224, SHA-256, SHA-384, or SHA-512).
`OutType`	`sha224()`	Returns the SHA-224 hash of the string argument; null if string is null.
`OutType`	`sha256()`	Returns the SHA-256 hash of the string argument; null if string is null.
`OutType`	`sha384()`	Returns the SHA-384 hash of the string argument; null if string is null.
`OutType`	`sha512()`	Returns the SHA-512 hash of the string argument; null if string is null.
`OutType`	`sign()`	Calculates the signum of a given number.
`OutType`	`similar(InType pattern)`	Returns true, if a string matches the specified SQL regex pattern.
`OutType`	`sin()`	Calculates the sine of a given number.
`OutType`	`sinh()`	Calculates the hyperbolic sine of a given value.
`OutType`	`splitIndex(InType separator, InType index)`	Split target string with custom separator and pick the index-th(start with 0) result.
`OutType`	`sqrt()`	Calculates the square root of a given value.
`OutType`	`start()`	Returns the start time (inclusive) of a window when applied on a window reference.
`OutType`	`stddevPop()`	Returns the population standard deviation of an expression (the square root of varPop()).
`OutType`	`stddevSamp()`	Returns the sample standard deviation of an expression (the square root of varSamp()).
`OutType`	`strToMap()`	Creates a map by parsing text.
`OutType`	`strToMap(InType listDelimiter, InType keyValueDelimiter)`	Creates a map by parsing text.
`OutType`	`substr(InType beginIndex)`	Creates a substring of the given string beginning at the given index to the end.
`OutType`	`substr(InType beginIndex, InType length)`	Creates a substring of the given string at given index for a given length.
`OutType`	`substring(InType beginIndex)`	Creates a substring of the given string beginning at the given index to the end.
`OutType`	`substring(InType beginIndex, InType length)`	Creates a substring of the given string at given index for a given length.
`OutType`	`sum()`	Returns the sum of the numeric field across all input values.
`OutType`	`sum0()`	Returns the sum of the numeric field across all input values.
`OutType`	`tan()`	Calculates the tangent of a given number.
`OutType`	`tanh()`	Calculates the hyperbolic tangent of a given number.
`OutType`	`then(InType ifTrue, InType ifFalse)`	Ternary conditional operator that decides which of two other expressions should be evaluated based on a evaluated boolean condition.
`OutType`	`times(InType other)`	Returns left multiplied by right.
`protected abstract OutType`	`toApiSpecificExpression(org.apache.flink.table.expressions.Expression expression)`
`OutType`	`toBase64()`	Returns the base64-encoded result of the input string.
`OutType`	`toDate()`	Parses a date string in the form "yyyy-MM-dd" to a SQL Date.
`protected abstract org.apache.flink.table.expressions.Expression`	`toExpr()`
`OutType`	`toTime()`	Parses a time string in the form "HH:mm:ss" to a SQL Time.
`OutType`	`toTimestamp()`	Parses a timestamp string in the form "yyyy-MM-dd HH:mm:ss[.SSS]" to a SQL Timestamp.
`OutType`	`trim()`	Removes leading and trailing space characters from the given string.
`OutType`	`trim(InType character)`	Removes leading and trailing characters from the given string.
`OutType`	`trimLeading()`	Removes leading space characters from the given string.
`OutType`	`trimLeading(InType character)`	Removes leading characters from the given string.
`OutType`	`trimTrailing()`	Removes trailing space characters from the given string.
`OutType`	`trimTrailing(InType character)`	Removes trailing characters from the given string.
`OutType`	`truncate()`	Returns a number of truncated to 0 decimal places.
`OutType`	`truncate(InType n)`	Returns a number of truncated to n decimal places.
`OutType`	`tryCast(org.apache.flink.table.types.DataType toType)`	Like `cast(DataType)`, but in case of error, returns `null` rather than failing the job.
`OutType`	`upperCase()`	Returns all of the characters in a string in upper case using the rules of the default locale.
`OutType`	`varPop()`	Returns the population standard variance of an expression.
`OutType`	`varSamp()`	Returns the sample variance of a given expression.
`OutType`	`week()`	Creates an interval of the given number of weeks.
`OutType`	`weeks()`	Creates an interval of the given number of weeks.
`OutType`	`year()`	Creates an interval of the given number of years.
`OutType`	`years()`	Creates an interval of the given number of years.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - BaseExpressions
```
public BaseExpressions()
```
- Method Detail
  - toExpr
```
protected abstract org.apache.flink.table.expressions.Expression toExpr()
```
  - toApiSpecificExpression
```
protected abstract OutType toApiSpecificExpression(org.apache.flink.table.expressions.Expression expression)
```
  - as
```
public OutType as(String name,
                  String... extraNames)
```
    Specifies a name for an expression i.e. a field.
    
    Parameters:
    
    name - name for one field
    
    extraNames - additional names if the expression expands to multiple fields
  - and
```
public OutType and(InType other)
```
    Boolean AND in three-valued logic. This is an infix notation. See also Expressions.and(Object, Object, Object...) for prefix notation with multiple arguments.
    
    See Also:
    
    Expressions.and(Object, Object, Object...)
  - or
```
public OutType or(InType other)
```
    Boolean OR in three-valued logic. This is an infix notation. See also Expressions.or(Object, Object, Object...) for prefix notation with multiple arguments.
    
    See Also:
    
    Expressions.or(Object, Object, Object...)
  - not
```
public OutType not()
```
    Inverts a given boolean expression.
    This method supports a three-valued logic by preserving NULL. This means if the input expression is NULL, the result will also be NULL.
    The resulting type is nullable if and only if the input type is nullable.
    Examples:
    lit(true).not() // false lit(false).not() // true lit(null, DataTypes.BOOLEAN()).not() // null
  - isGreater
```
public OutType isGreater(InType other)
```
    Greater than.
  - isGreaterOrEqual
```
public OutType isGreaterOrEqual(InType other)
```
    Greater than or equal.
  - isLess
```
public OutType isLess(InType other)
```
    Less than.
  - isLessOrEqual
```
public OutType isLessOrEqual(InType other)
```
    Less than or equal.
  - isEqual
```
public OutType isEqual(InType other)
```
    Equals.
  - isNotEqual
```
public OutType isNotEqual(InType other)
```
    Not equal.
  - plus
```
public OutType plus(InType other)
```
    Returns left plus right.
  - minus
```
public OutType minus(InType other)
```
    Returns left minus right.
  - dividedBy
```
public OutType dividedBy(InType other)
```
    Returns left divided by right.
  - times
```
public OutType times(InType other)
```
    Returns left multiplied by right.
  - between
```
public OutType between(InType lowerBound,
                       InType upperBound)
```
    Returns true if the given expression is between lowerBound and upperBound (both inclusive). False otherwise. The parameters must be numeric types or identical comparable types.
    
    Parameters:
    
    lowerBound - numeric or comparable expression
    
    upperBound - numeric or comparable expression
  - notBetween
```
public OutType notBetween(InType lowerBound,
                          InType upperBound)
```
    Returns true if the given expression is not between lowerBound and upperBound (both inclusive). False otherwise. The parameters must be numeric types or identical comparable types.
    
    Parameters:
    
    lowerBound - numeric or comparable expression
    
    upperBound - numeric or comparable expression
  - then
```
public OutType then(InType ifTrue,
                    InType ifFalse)
```
    Ternary conditional operator that decides which of two other expressions should be evaluated based on a evaluated boolean condition.
    e.g. lit(42).isGreater(5).then("A", "B") leads to "A"
    
    Parameters:
    
    ifTrue - expression to be evaluated if condition holds
    
    ifFalse - expression to be evaluated if condition does not hold
  - ifNull
```
public OutType ifNull(InType nullReplacement)
```
    Returns nullReplacement if the given expression is NULL; otherwise the expression is returned.
    This function returns a data type that is very specific in terms of nullability. The returned type is the common type of both arguments but only nullable if the nullReplacement is nullable.
    The function allows to pass nullable columns into a function or table that is declared with a NOT NULL constraint.
    E.g., $('nullable_column').ifNull(5) returns never NULL.
  - isNull
```
public OutType isNull()
```
    Returns true if the given expression is null.
  - isNotNull
```
public OutType isNotNull()
```
    Returns true if the given expression is not null.
  - isTrue
```
public OutType isTrue()
```
    Returns true if given boolean expression is true. False otherwise (for null and false).
  - isFalse
```
public OutType isFalse()
```
    Returns true if given boolean expression is false. False otherwise (for null and true).
  - isNotTrue
```
public OutType isNotTrue()
```
    Returns true if given boolean expression is not true (for null and false). False otherwise.
  - isNotFalse
```
public OutType isNotFalse()
```
    Returns true if given boolean expression is not false (for null and true). False otherwise.
  - distinct
```
public OutType distinct()
```
    Similar to a SQL distinct aggregation clause such as COUNT(DISTINCT a), declares that an aggregation function is only applied on distinct input values.
    For example:
    orders .groupBy($("a")) .select($("a"), $("b").sum().distinct().as("d"))
  - sum
```
public OutType sum()
```
    Returns the sum of the numeric field across all input values. If all values are null, null is returned.
  - sum0
```
public OutType sum0()
```
    Returns the sum of the numeric field across all input values. If all values are null, 0 is returned.
  - min
```
public OutType min()
```
    Returns the minimum value of field across all input values.
  - max
```
public OutType max()
```
    Returns the maximum value of field across all input values.
  - count
```
public OutType count()
```
    Returns the number of input rows for which the field is not null.
  - avg
```
public OutType avg()
```
    Returns the average (arithmetic mean) of the numeric field across all input values.
  - firstValue
```
public OutType firstValue()
```
    Returns the first value of field across all input values.
  - lastValue
```
public OutType lastValue()
```
    Returns the last value of field across all input values.
  - listAgg
```
public OutType listAgg()
```
    Concatenates the values of string expressions and places separator(,) values between them. The separator is not added at the end of string.
  - listAgg
```
public OutType listAgg(String separator)
```
    Concatenates the values of string expressions and places separator values between them. The separator is not added at the end of string. The default value of separator is ‘,’.
    
    Parameters:
    
    separator - string containing the character
  - stddevPop
```
public OutType stddevPop()
```
    Returns the population standard deviation of an expression (the square root of varPop()).
  - stddevSamp
```
public OutType stddevSamp()
```
    Returns the sample standard deviation of an expression (the square root of varSamp()).
  - varPop
```
public OutType varPop()
```
    Returns the population standard variance of an expression.
  - varSamp
```
public OutType varSamp()
```
    Returns the sample variance of a given expression.
  - collect
```
public OutType collect()
```
    Returns multiset aggregate of a given expression.
  - cast
```
public OutType cast(org.apache.flink.table.types.DataType toType)
```
    Returns a new value being cast to toType. A cast error throws an exception and fails the job. When performing a cast operation that may fail, like DataTypes.STRING() to DataTypes.INT(), one should rather use tryCast(DataType), in order to handle errors. If ExecutionConfigOptions.TABLE_EXEC_LEGACY_CAST_BEHAVIOUR is enabled, this function behaves like tryCast(DataType).
    E.g. "42".cast(DataTypes.INT()) returns 42; null.cast(DataTypes.STRING()) returns null of type DataTypes.STRING(); "non-number".cast(DataTypes.INT()) throws an exception and fails the job.
  - tryCast
```
public OutType tryCast(org.apache.flink.table.types.DataType toType)
```
    Like cast(DataType), but in case of error, returns null rather than failing the job.
    E.g. "42".tryCast(DataTypes.INT()) returns 42; null.tryCast(DataTypes.STRING()) returns null of type DataTypes.STRING(); "non-number".tryCast(DataTypes.INT()) returns null of type DataTypes.INT(); coalesce("non-number".tryCast(DataTypes.INT()), 0) returns 0 of type DataTypes.INT().
  - cast
```
@Deprecated
public OutType cast(org.apache.flink.api.common.typeinfo.TypeInformation<?> toType)
```
    Deprecated.
    This method will be removed in future versions as it uses the old type system. It is recommended to use cast(DataType) instead which uses the new type system based on DataTypes. Please make sure to use either the old or the new type system consistently to avoid unintended behavior. See the website documentation for more information.
  - asc
```
public OutType asc()
```
    Specifies ascending order of an expression i.e. a field for orderBy unresolvedCall.
  - desc
```
public OutType desc()
```
    Specifies descending order of an expression i.e. a field for orderBy unresolvedCall.
  - in
```
@SafeVarargs
public final OutType in(InType... elements)
```
    Returns true if an expression exists in a given list of expressions. This is a shorthand for multiple OR conditions.
    If the testing set contains null, the result will be null if the element can not be found and true if it can be found. If the element is null, the result is always null.
    e.g. lit("42").in(1, 2, 3) leads to false.
  - in
```
public OutType in(Table table)
```
    Returns true if an expression exists in a given table sub-query. The sub-query table must consist of one column. This column must have the same data type as the expression.
    Note: This operation is not supported in a streaming environment yet.
  - start
```
public OutType start()
```
    Returns the start time (inclusive) of a window when applied on a window reference.
  - end
```
public OutType end()
```
    Returns the end time (exclusive) of a window when applied on a window reference.
    e.g. if a window ends at 10:59:59.999 this property will return 11:00:00.000.
  - mod
```
public OutType mod(InType other)
```
    Calculates the remainder of division the given number by another one.
  - exp
```
public OutType exp()
```
    Calculates the Euler's number raised to the given power.
  - log10
```
public OutType log10()
```
    Calculates the base 10 logarithm of the given value.
  - log2
```
public OutType log2()
```
    Calculates the base 2 logarithm of the given value.
  - ln
```
public OutType ln()
```
    Calculates the natural logarithm of the given value.
  - log
```
public OutType log()
```
    Calculates the natural logarithm of the given value.
  - log
```
public OutType log(InType base)
```
    Calculates the logarithm of the given value to the given base.
  - power
```
public OutType power(InType other)
```
    Calculates the given number raised to the power of the other value.
  - cosh
```
public OutType cosh()
```
    Calculates the hyperbolic cosine of a given value.
  - sqrt
```
public OutType sqrt()
```
    Calculates the square root of a given value.
  - abs
```
public OutType abs()
```
    Calculates the absolute value of given value.
  - floor
```
public OutType floor()
```
    Calculates the largest integer less than or equal to a given number.
  - sinh
```
public OutType sinh()
```
    Calculates the hyperbolic sine of a given value.
  - ceil
```
public OutType ceil()
```
    Calculates the smallest integer greater than or equal to a given number.
  - sin
```
public OutType sin()
```
    Calculates the sine of a given number.
  - cos
```
public OutType cos()
```
    Calculates the cosine of a given number.
  - tan
```
public OutType tan()
```
    Calculates the tangent of a given number.
  - cot
```
public OutType cot()
```
    Calculates the cotangent of a given number.
  - asin
```
public OutType asin()
```
    Calculates the arc sine of a given number.
  - acos
```
public OutType acos()
```
    Calculates the arc cosine of a given number.
  - atan
```
public OutType atan()
```
    Calculates the arc tangent of a given number.
  - tanh
```
public OutType tanh()
```
    Calculates the hyperbolic tangent of a given number.
  - degrees
```
public OutType degrees()
```
    Converts numeric from radians to degrees.
  - radians
```
public OutType radians()
```
    Converts numeric from degrees to radians.
  - sign
```
public OutType sign()
```
    Calculates the signum of a given number.
  - round
```
public OutType round(InType places)
```
    Rounds the given number to integer places right to the decimal point.
  - bin
```
public OutType bin()
```
    Returns a string representation of an integer numeric value in binary format. Returns null if numeric is null. E.g. "4" leads to "100", "12" leads to "1100".
  - hex
```
public OutType hex()
```
    Returns a string representation of an integer numeric value or a string in hex format. Returns null if numeric or string is null.
    E.g. a numeric 20 leads to "14", a numeric 100 leads to "64", and a string "hello,world" leads to "68656c6c6f2c776f726c64".
  - truncate
```
public OutType truncate(InType n)
```
    Returns a number of truncated to n decimal places. If n is 0,the result has no decimal point or fractional part. n can be negative to cause n digits left of the decimal point of the value to become zero. E.g. truncate(42.345, 2) to 42.34.
  - truncate
```
public OutType truncate()
```
    Returns a number of truncated to 0 decimal places. E.g. truncate(42.345) to 42.0.
  - substring
```
public OutType substring(InType beginIndex,
                         InType length)
```
    Creates a substring of the given string at given index for a given length.
    
    Parameters:
    
    beginIndex - first character of the substring (starting at 1, inclusive)
    
    length - number of characters of the substring
  - substring
```
public OutType substring(InType beginIndex)
```
    Creates a substring of the given string beginning at the given index to the end.
    
    Parameters:
    
    beginIndex - first character of the substring (starting at 1, inclusive)
  - substr
```
public OutType substr(InType beginIndex,
                      InType length)
```
    Creates a substring of the given string at given index for a given length.
    
    Parameters:
    
    beginIndex - first character of the substring (starting at 1, inclusive)
    
    length - number of characters of the substring
  - substr
```
public OutType substr(InType beginIndex)
```
    Creates a substring of the given string beginning at the given index to the end.
    
    Parameters:
    
    beginIndex - first character of the substring (starting at 1, inclusive)
  - trimLeading
```
public OutType trimLeading()
```
    Removes leading space characters from the given string.
  - trimLeading
```
public OutType trimLeading(InType character)
```
    Removes leading characters from the given string.
    
    Parameters:
    
    character - string containing the character
  - trimTrailing
```
public OutType trimTrailing()
```
    Removes trailing space characters from the given string.
  - trimTrailing
```
public OutType trimTrailing(InType character)
```
    Removes trailing characters from the given string.
    
    Parameters:
    
    character - string containing the character
  - trim
```
public OutType trim()
```
    Removes leading and trailing space characters from the given string.
  - trim
```
public OutType trim(InType character)
```
    Removes leading and trailing characters from the given string.
    
    Parameters:
    
    character - string containing the character
  - replace
```
public OutType replace(InType search,
                       InType replacement)
```
    Returns a new string which replaces all the occurrences of the search target with the replacement string (non-overlapping).
  - charLength
```
public OutType charLength()
```
    Returns the length of a string.
  - upperCase
```
public OutType upperCase()
```
    Returns all of the characters in a string in upper case using the rules of the default locale.
  - lowerCase
```
public OutType lowerCase()
```
    Returns all of the characters in a string in lower case using the rules of the default locale.
  - initCap
```
public OutType initCap()
```
    Converts the initial letter of each word in a string to uppercase. Assumes a string containing only [A-Za-z0-9], everything else is treated as whitespace.
  - like
```
public OutType like(InType pattern)
```
    Returns true, if a string matches the specified LIKE pattern.
    e.g. "Jo_n%" matches all strings that start with "Jo(arbitrary letter)n"
  - similar
```
public OutType similar(InType pattern)
```
    Returns true, if a string matches the specified SQL regex pattern.
    e.g. "A+" matches all strings that consist of at least one A
  - position
```
public OutType position(InType haystack)
```
    Returns the position of string in an other string starting at 1. Returns 0 if string could not be found.
    e.g. lit("a").position("bbbbba") leads to 6
  - lpad
```
public OutType lpad(InType len,
                    InType pad)
```
    Returns a string left-padded with the given pad string to a length of len characters. If the string is longer than len, the return value is shortened to len characters.
    e.g. lit("hi").lpad(4, "??") returns "??hi", lit("hi").lpad(1, '??') returns "h"
  - rpad
```
public OutType rpad(InType len,
                    InType pad)
```
    Returns a string right-padded with the given pad string to a length of len characters. If the string is longer than len, the return value is shortened to len characters.
    e.g. lit("hi").rpad(4, "??") returns "hi??", lit("hi").rpad(1, '??') returns "h"
  - over
```
public OutType over(InType alias)
```
    Defines an aggregation to be used for a previously specified over window.
    For example:
    table .window(Over partitionBy 'c orderBy 'rowtime preceding 2.rows following CURRENT_ROW as 'w) .select('c, 'a, 'a.count over 'w, 'a.sum over 'w)
  - overlay
```
public OutType overlay(InType newString,
                       InType starting)
```
    Replaces a substring of string with a string starting at a position (starting at 1).
    e.g. lit("xxxxxtest").overlay("xxxx", 6) leads to "xxxxxxxxx"
  - overlay
```
public OutType overlay(InType newString,
                       InType starting,
                       InType length)
```
    Replaces a substring of string with a string starting at a position (starting at 1). The length specifies how many characters should be removed.
    e.g. lit("xxxxxtest").overlay("xxxx", 6, 2) leads to "xxxxxxxxxst"
  - regexp
```
public OutType regexp(InType regex)
```
    Returns TRUE if any (possibly empty) substring matches the Java regular expression, otherwise FALSE. Returns NULL if any of arguments is NULL.
  - regexpReplace
```
public OutType regexpReplace(InType regex,
                             InType replacement)
```
    Returns a string with all substrings that match the regular expression consecutively being replaced.
  - regexpExtract
```
public OutType regexpExtract(InType regex,
                             InType extractIndex)
```
    Returns a string extracted with a specified regular expression and a regex match group index.
  - regexpExtract
```
public OutType regexpExtract(InType regex)
```
    Returns a string extracted with a specified regular expression.
  - fromBase64
```
public OutType fromBase64()
```
    Returns the base string decoded with base64.
  - toBase64
```
public OutType toBase64()
```
    Returns the base64-encoded result of the input string.
  - ascii
```
public OutType ascii()
```
    Returns the numeric value of the first character of the input string.
  - chr
```
public OutType chr()
```
    Returns the ASCII character result of the input integer.
  - decode
```
public OutType decode(InType charset)
```
    Decodes the first argument into a String using the provided character set.
  - encode
```
public OutType encode(InType charset)
```
    Encodes the string into a BINARY using the provided character set.
  - left
```
public OutType left(InType len)
```
    Returns the leftmost integer characters from the input string.
  - right
```
public OutType right(InType len)
```
    Returns the rightmost integer characters from the input string.
  - instr
```
public OutType instr(InType str)
```
    Returns the position of the first occurrence of the input string.
  - locate
```
public OutType locate(InType str)
```
    Returns the position of the first occurrence in the input string.
  - locate
```
public OutType locate(InType str,
                      InType pos)
```
    Returns the position of the first occurrence in the input string after position integer.
  - parseUrl
```
public OutType parseUrl(InType partToExtract)
```
    Parse url and return various parameter of the URL. If accept any null arguments, return null.
  - parseUrl
```
public OutType parseUrl(InType partToExtract,
                        InType key)
```
    Parse url and return various parameter of the URL. If accept any null arguments, return null.
  - ltrim
```
public OutType ltrim()
```
    Returns a string that removes the left whitespaces from the given string.
  - rtrim
```
public OutType rtrim()
```
    Returns a string that removes the right whitespaces from the given string.
  - repeat
```
public OutType repeat(InType n)
```
    Returns a string that repeats the base string n times.
  - reverse
```
public OutType reverse()
```
    Reverse each character in current string.
    
    Returns:
    
    a new string which character order is reverse to current string.
  - splitIndex
```
public OutType splitIndex(InType separator,
                          InType index)
```
    Split target string with custom separator and pick the index-th(start with 0) result.
    
    Parameters:
    
    separator - custom separator.
    
    index - index of the result which you want.
    
    Returns:
    
    the string at the index of split results.
  - strToMap
```
public OutType strToMap()
```
    Creates a map by parsing text. Split text into key-value pairs using two delimiters. The first delimiter separates pairs, and the second delimiter separates key and value. If only one parameter is given, default delimiters are used: ',' as delimiter1 and '=' as delimiter2. Both delimiters are treated as regular expressions.
    
    Returns:
    
    the map
  - strToMap
```
public OutType strToMap(InType listDelimiter,
                        InType keyValueDelimiter)
```
    Creates a map by parsing text. Split text into key-value pairs using two delimiters. The first delimiter separates pairs, and the second delimiter separates key and value. Both listDelimiter and keyValueDelimiter are treated as regular expressions.
    
    Parameters:
    
    listDelimiter - the delimiter to separates pairs
    
    keyValueDelimiter - the delimiter to separates key and value
    
    Returns:
    
    the map
  - toDate
```
public OutType toDate()
```
    Parses a date string in the form "yyyy-MM-dd" to a SQL Date.
  - toTime
```
public OutType toTime()
```
    Parses a time string in the form "HH:mm:ss" to a SQL Time.
  - toTimestamp
```
public OutType toTimestamp()
```
    Parses a timestamp string in the form "yyyy-MM-dd HH:mm:ss[.SSS]" to a SQL Timestamp.
  - extract
```
public OutType extract(org.apache.flink.table.expressions.TimeIntervalUnit timeIntervalUnit)
```
    Extracts parts of a time point or time interval. Returns the part as a long value.
    e.g. lit("2006-06-05").toDate().extract(DAY) leads to 5
  - floor
```
public OutType floor(org.apache.flink.table.expressions.TimeIntervalUnit timeIntervalUnit)
```
    Rounds down a time point to the given unit.
    e.g. lit("12:44:31").toDate().floor(MINUTE) leads to 12:44:00
  - ceil
```
public OutType ceil(org.apache.flink.table.expressions.TimeIntervalUnit timeIntervalUnit)
```
    Rounds up a time point to the given unit.
    e.g. lit("12:44:31").toDate().ceil(MINUTE) leads to 12:45:00
  - get
```
public OutType get(String name)
```
    Accesses the field of a Flink composite type (such as Tuple, POJO, etc.) by name and returns it's value.
    
    Parameters:
    
    name - name of the field (similar to Flink's field expressions)
  - get
```
public OutType get(int index)
```
    Accesses the field of a Flink composite type (such as Tuple, POJO, etc.) by index and returns it's value.
    
    Parameters:
    
    index - position of the field
  - flatten
```
public OutType flatten()
```
    Converts a Flink composite type (such as Tuple, POJO, etc.) and all of its direct subtypes into a flat representation where every subtype is a separate field.
  - at
```
public OutType at(InType index)
```
    Accesses the element of an array or map based on a key or an index (starting at 1).
    
    Parameters:
    
    index - key or position of the element (array index starting at 1)
  - cardinality
```
public OutType cardinality()
```
    Returns the number of elements of an array or number of entries of a map.
  - element
```
public OutType element()
```
    Returns the sole element of an array with a single element. Returns null if the array is empty. Throws an exception if the array has more than one element.
  - arrayContains
```
public OutType arrayContains(InType needle)
```
    Returns whether the given element exists in an array.
    Checking for null elements in the array is supported. If the array itself is null, the function will return null. The given element is cast implicitly to the array's element type if necessary.
  - arrayDistinct
```
public OutType arrayDistinct()
```
    Returns an array with unique elements.
    If the array itself is null, the function will return null. Keeps ordering of elements.
  - arrayPosition
```
public OutType arrayPosition(InType needle)
```
    Returns the position of the first occurrence of element in the given array as int. Returns 0 if the given value could not be found in the array. Returns null if either of the arguments are null
    NOTE: that this is not zero based, but 1-based index. The first element in the array has index 1.
  - arrayRemove
```
public OutType arrayRemove(InType needle)
```
    Removes all elements that equal to element from array.
    If the array itself is null, the function will return null. Keeps ordering of elements.
  - arrayReverse
```
public OutType arrayReverse()
```
    Returns an array in reverse order.
    If the array itself is null, the function will return null.
  - arraySlice
```
public OutType arraySlice(InType startOffset,
                          InType endOffset)
```
    Returns a subarray of the input array between 'start_offset' and 'end_offset' inclusive. The offsets are 1-based however 0 is also treated as the beginning of the array. Positive values are counted from the beginning of the array while negative from the end. If 'end_offset' is omitted then this offset is treated as the length of the array. If 'start_offset' is after 'end_offset' or both are out of array bounds an empty array will be returned.
    Returns null if any input is null.
  - arraySlice
```
public OutType arraySlice(InType startOffset)
```
  - arrayUnion
```
public OutType arrayUnion(InType array)
```
    Returns an array of the elements in the union of array1 and array2, without duplicates.
    If any of the array is null, the function will return null.
  - arrayConcat
```
public OutType arrayConcat(InType... arrays)
```
    Returns an array that is the result of concatenating at least one array. This array contains all the elements in the first array, followed by all the elements in the second array, and so forth, up to the Nth array.
    If any input array is NULL, the function returns NULL.
  - arrayMax
```
public OutType arrayMax()
```
    Returns the maximum value from the array.
    if array itself is null, the function returns null.
  - arrayMin
```
public OutType arrayMin()
```
    Returns the minimum value from the array.
    if array itself is null, the function returns null.
  - mapKeys
```
public OutType mapKeys()
```
    Returns the keys of the map as an array.
  - mapValues
```
public OutType mapValues()
```
    Returns the values of the map as an array.
  - mapEntries
```
public OutType mapEntries()
```
    Returns an array of all entries in the given map.
  - rowtime
```
public OutType rowtime()
```
    Declares a field as the rowtime attribute for indicating, accessing, and working in Flink's event time.
  - proctime
```
public OutType proctime()
```
    Declares a field as the proctime attribute for indicating, accessing, and working in Flink's processing time.
  - year
```
public OutType year()
```
    Creates an interval of the given number of years.
    The produced expression is of type DataTypes.INTERVAL
  - years
```
public OutType years()
```
    Creates an interval of the given number of years.
  - quarter
```
public OutType quarter()
```
    Creates an interval of the given number of quarters.
  - quarters
```
public OutType quarters()
```
    Creates an interval of the given number of quarters.
  - month
```
public OutType month()
```
    Creates an interval of the given number of months.
  - months
```
public OutType months()
```
    Creates an interval of the given number of months.
  - week
```
public OutType week()
```
    Creates an interval of the given number of weeks.
  - weeks
```
public OutType weeks()
```
    Creates an interval of the given number of weeks.
  - day
```
public OutType day()
```
    Creates an interval of the given number of days.
  - days
```
public OutType days()
```
    Creates an interval of the given number of days.
  - hour
```
public OutType hour()
```
    Creates an interval of the given number of hours.
  - hours
```
public OutType hours()
```
    Creates an interval of the given number of hours.
  - minute
```
public OutType minute()
```
    Creates an interval of the given number of minutes.
  - minutes
```
public OutType minutes()
```
    Creates an interval of the given number of minutes.
  - second
```
public OutType second()
```
    Creates an interval of the given number of seconds.
  - seconds
```
public OutType seconds()
```
    Creates an interval of the given number of seconds.
  - milli
```
public OutType milli()
```
    Creates an interval of the given number of milliseconds.
  - millis
```
public OutType millis()
```
    Creates an interval of the given number of milliseconds.
  - md5
```
public OutType md5()
```
    Returns the MD5 hash of the string argument; null if string is null.
    
    Returns:
    
    string of 32 hexadecimal digits or null
  - sha1
```
public OutType sha1()
```
    Returns the SHA-1 hash of the string argument; null if string is null.
    
    Returns:
    
    string of 40 hexadecimal digits or null
  - sha224
```
public OutType sha224()
```
    Returns the SHA-224 hash of the string argument; null if string is null.
    
    Returns:
    
    string of 56 hexadecimal digits or null
  - sha256
```
public OutType sha256()
```
    Returns the SHA-256 hash of the string argument; null if string is null.
    
    Returns:
    
    string of 64 hexadecimal digits or null
  - sha384
```
public OutType sha384()
```
    Returns the SHA-384 hash of the string argument; null if string is null.
    
    Returns:
    
    string of 96 hexadecimal digits or null
  - sha512
```
public OutType sha512()
```
    Returns the SHA-512 hash of the string argument; null if string is null.
    
    Returns:
    
    string of 128 hexadecimal digits or null
  - sha2
```
public OutType sha2(InType hashLength)
```
    Returns the hash for the given string expression using the SHA-2 family of hash functions (SHA-224, SHA-256, SHA-384, or SHA-512).
    
    Parameters:
    
    hashLength - bit length of the result (either 224, 256, 384, or 512)
    
    Returns:
    
    string or null if one of the arguments is null.
  - isJson
```
public OutType isJson(org.apache.flink.table.api.JsonType type)
```
    Determine whether a given string is valid JSON.
    Specifying the optional {@param type} argument puts a constraint on which type of JSON object is allowed. If the string is valid JSON, but not that type, false is returned. The default is JsonType.VALUE.
    Examples:
    lit("1").isJson() // true lit("[]").isJson() // true lit("{}").isJson() // true lit("\"abc\"").isJson() // true lit("abc").isJson() // false nullOf(DataTypes.STRING()).isJson() // false lit("1").isJson(JsonType.SCALAR) // true lit("1").isJson(JsonType.ARRAY) // false lit("1").isJson(JsonType.OBJECT) // false lit("{}").isJson(JsonType.SCALAR) // false lit("{}").isJson(JsonType.ARRAY) // false lit("{}").isJson(JsonType.OBJECT) // true
    Parameters:
    
    type - The type of JSON object to validate against.
    
    Returns:
    
    true if the string is a valid JSON of the given {@param type}, false otherwise.
  - isJson
```
public OutType isJson()
```
    Determine whether a given string is valid JSON.
    This is a shortcut for isJson(JsonType.VALUE). See isJson(JsonType).
    
    Returns:
    
    true if the string is a valid JSON value, false otherwise.
  - jsonExists
```
public OutType jsonExists(String path,
                          org.apache.flink.table.api.JsonExistsOnError onError)
```
    Returns whether a JSON string satisfies a given search criterion.
    This follows the ISO/IEC TR 19075-6 specification for JSON support in SQL.
    Examples:
    // true lit("{\"a\": true}").jsonExists("$.a") // false lit("{\"a\": true}").jsonExists("$.b") // true lit("{\"a\": [{ \"b\": 1 }]}").jsonExists("$.a[0].b") // true lit("{\"a\": true}").jsonExists("strict $.b", JsonExistsOnError.TRUE) // false lit("{\"a\": true}").jsonExists("strict $.b", JsonExistsOnError.FALSE)
    Parameters:
    
    path - JSON path to search for.
    
    onError - Behavior in case of an error.
    
    Returns:
    
    true if the JSON string satisfies the search criterion.
  - jsonExists
```
public OutType jsonExists(String path)
```
    Determines whether a JSON string satisfies a given search criterion.
    This follows the ISO/IEC TR 19075-6 specification for JSON support in SQL.
    Examples:
    // true lit("{\"a\": true}").jsonExists("$.a") // false lit("{\"a\": true}").jsonExists("$.b") // true lit("{\"a\": [{ \"b\": 1 }]}").jsonExists("$.a[0].b") // true lit("{\"a\": true}").jsonExists("strict $.b", JsonExistsOnError.TRUE) // false lit("{\"a\": true}").jsonExists("strict $.b", JsonExistsOnError.FALSE)
    Parameters:
    
    path - JSON path to search for.
    
    Returns:
    
    true if the JSON string satisfies the search criterion.
  - jsonValue
```
public OutType jsonValue(String path,
                         org.apache.flink.table.types.DataType returningType,
                         org.apache.flink.table.api.JsonValueOnEmptyOrError onEmpty,
                         InType defaultOnEmpty,
                         org.apache.flink.table.api.JsonValueOnEmptyOrError onError,
                         InType defaultOnError)
```
    Extracts a scalar from a JSON string.
    This method searches a JSON string for a given path expression and returns the value if the value at that path is scalar. Non-scalar values cannot be returned. By default, the value is returned as DataTypes.STRING(). Using {@param returningType} a different type can be chosen, with the following types being supported:
    
    DataTypes.STRING()
    DataTypes.BOOLEAN()
    DataTypes.INT()
    DataTypes.DOUBLE()
    
    For empty path expressions or errors a behavior can be defined to either return null, raise an error or return a defined default value instead.
    See jsonQuery(String, JsonQueryWrapper, JsonQueryOnEmptyOrError, JsonQueryOnEmptyOrError) for extracting non-scalar values from a JSON string.
    Examples:
    // STRING: "true" lit("{\"a\": true}").jsonValue("$.a") // DOUBLE: 0.998 lit("{\"a.b\": [0.998,0.996]}").jsonValue("$.['a.b'][0]", DataTypes.DOUBLE()) // BOOLEAN: true lit("{\"a\": true}").jsonValue("$.a", DataTypes.BOOLEAN()) // BOOLEAN: "false" lit("{\"a\": true}").jsonValue("lax $.b", JsonValueOnEmptyOrError.DEFAULT, false, JsonValueOnEmptyOrError.NULL, null) // BOOLEAN: "false" lit("{\"a\": true}").jsonValue("strict $.b", JsonValueOnEmptyOrError.NULL, null, JsonValueOnEmptyOrError.DEFAULT, false)
    Parameters:
    
    path - JSON path to extract.
    
    returningType - Type to convert the extracted scalar to, otherwise defaults to DataTypes.STRING().
    
    onEmpty - Behavior in case the path expression is empty.
    
    defaultOnEmpty - Default value to return if the path expression is empty and {@param onEmpty} is set to JsonValueOnEmptyOrError.DEFAULT.
    
    onError - Behavior in case of an error.
    
    defaultOnError - Default value to return if there is an error and {@param onError} is set to JsonValueOnEmptyOrError.DEFAULT.
    
    Returns:
    
    The extracted scalar value.
  - jsonValue
```
public OutType jsonValue(String path,
                         org.apache.flink.table.types.DataType returningType)
```
    Extracts a scalar from a JSON string.
    This method searches a JSON string for a given path expression and returns the value if the value at that path is scalar. Non-scalar values cannot be returned. By default, the value is returned as DataTypes.STRING().
    See also jsonValue(String, DataType, JsonValueOnEmptyOrError, Object, JsonValueOnEmptyOrError, Object).
    
    Parameters:
    
    path - JSON path to extract.
    
    returningType - Type to convert the extracted scalar to, otherwise defaults to DataTypes.STRING().
    
    Returns:
    
    The extracted scalar value.
  - jsonValue
```
public OutType jsonValue(String path,
                         org.apache.flink.table.types.DataType returningType,
                         InType defaultOnEmptyOrError)
```
    Extracts a scalar from a JSON string.
    This method searches a JSON string for a given path expression and returns the value if the value at that path is scalar. Non-scalar values cannot be returned. By default, the value is returned as DataTypes.STRING().
    See also jsonValue(String, DataType, JsonValueOnEmptyOrError, Object, JsonValueOnEmptyOrError, Object).
    This is a convenience method using JsonValueOnEmptyOrError.DEFAULT for both empty and error cases with the same default value.
    
    Parameters:
    
    path - JSON path to extract.
    
    returningType - Type to convert the extracted scalar to, otherwise defaults to DataTypes.STRING().
    
    Returns:
    
    The extracted scalar value.
  - jsonValue
```
public OutType jsonValue(String path)
```
    Extracts a scalar from a JSON string.
    This method searches a JSON string for a given path expression and returns the value if the value at that path is scalar. Non-scalar values cannot be returned. By default, the value is returned as DataTypes.STRING().
    See also jsonValue(String, DataType, JsonValueOnEmptyOrError, Object, JsonValueOnEmptyOrError, Object).
    
    Parameters:
    
    path - JSON path to extract.
    
    Returns:
    
    The extracted scalar value.
  - jsonQuery
```
public OutType jsonQuery(String path,
                         org.apache.flink.table.api.JsonQueryWrapper wrappingBehavior,
                         org.apache.flink.table.api.JsonQueryOnEmptyOrError onEmpty,
                         org.apache.flink.table.api.JsonQueryOnEmptyOrError onError)
```
    Extracts JSON values from a JSON string.
    This follows the ISO/IEC TR 19075-6 specification for JSON support in SQL. The result is always returned as a DataTypes.STRING().
    The {@param wrappingBehavior} determines whether the extracted value should be wrapped into an array, and whether to do so unconditionally or only if the value itself isn't an array already.
    {@param onEmpty} and {@param onError} determine the behavior in case the path expression is empty, or in case an error was raised, respectively. By default, in both cases null is returned. Other choices are to use an empty array, an empty object, or to raise an error.
    See jsonValue(String, DataType, JsonValueOnEmptyOrError, Object, JsonValueOnEmptyOrError, Object) for extracting scalars from a JSON string.
    Examples:
    lit("{ \"a\": { \"b\": 1 } }").jsonQuery("$.a") // "{ \"b\": 1 }" lit("[1, 2]").jsonQuery("$") // "[1, 2]" nullOf(DataTypes.STRING()).jsonQuery("$") // null // Wrap result into an array lit("{}").jsonQuery("$", JsonQueryWrapper.CONDITIONAL_ARRAY) // "[{}]" lit("[1, 2]").jsonQuery("$", JsonQueryWrapper.CONDITIONAL_ARRAY) // "[1, 2]" lit("[1, 2]").jsonQuery("$", JsonQueryWrapper.UNCONDITIONAL_ARRAY) // "[[1, 2]]" // Scalars must be wrapped to be returned lit(1).jsonQuery("$") // null lit(1).jsonQuery("$", JsonQueryWrapper.CONDITIONAL_ARRAY) // "[1]" // Behavior if path expression is empty / there is an error // "{}" lit("{}").jsonQuery("lax $.invalid", JsonQueryWrapper.WITHOUT_ARRAY, JsonQueryOnEmptyOrError.EMPTY_OBJECT, JsonQueryOnEmptyOrError.NULL) // "[]" lit("{}").jsonQuery("strict $.invalid", JsonQueryWrapper.WITHOUT_ARRAY, JsonQueryOnEmptyOrError.NULL, JsonQueryOnEmptyOrError.EMPTY_ARRAY)
    Parameters:
    
    path - JSON path to search for.
    
    wrappingBehavior - Determine if and when to wrap the resulting value into an array.
    
    onEmpty - Behavior in case the path expression is empty.
    
    onError - Behavior in case of an error.
    
    Returns:
    
    The extracted JSON value.
  - jsonQuery
```
public OutType jsonQuery(String path,
                         org.apache.flink.table.api.JsonQueryWrapper wrappingBehavior)
```
    Extracts JSON values from a JSON string.
    The {@param wrappingBehavior} determines whether the extracted value should be wrapped into an array, and whether to do so unconditionally or only if the value itself isn't an array already.
    See also jsonQuery(String, JsonQueryWrapper, JsonQueryOnEmptyOrError, JsonQueryOnEmptyOrError).
    
    Parameters:
    
    path - JSON path to search for.
    
    wrappingBehavior - Determine if and when to wrap the resulting value into an array.
    
    Returns:
    
    The extracted JSON value.
  - jsonQuery
```
public OutType jsonQuery(String path)
```
    Extracts JSON values from a JSON string.
    See also jsonQuery(String, JsonQueryWrapper, JsonQueryOnEmptyOrError, JsonQueryOnEmptyOrError).
    
    Parameters:
    
    path - JSON path to search for.
    
    Returns:
    
    The extracted JSON value.

Class BaseExpressions<InType,​OutType>

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

BaseExpressions

Method Detail

toExpr

toApiSpecificExpression

as

and

or

not

isGreater

isGreaterOrEqual

isLess

isLessOrEqual

isEqual

isNotEqual

plus

minus

dividedBy

times

between

notBetween

then

ifNull

isNull

isNotNull

isTrue

isFalse

isNotTrue

isNotFalse

distinct

sum

sum0

min

max

count

avg

firstValue

lastValue

listAgg

listAgg

stddevPop

stddevSamp

varPop

varSamp

collect

cast

tryCast

cast

asc

desc

in

in

start

end

mod

exp

log10

log2

ln

log

log

power

cosh

sqrt

abs

floor

sinh

ceil

sin

cos

tan

cot

asin

acos

atan

tanh

Class BaseExpressions<InType,OutType>