Other Functions

**Table 1** Array functions
Function	Return Data Type	Description
CARDINALITY(ARRAY)	INT	Return the element count of an array.
ELEMENT(ARRAY)	-	Return the sole element of an array with a single element. If the array contains no elements, null is returned. If the array contains multiple elements, an exception is reported.

Example:

The returned number of elements in the array is 3.

insert into temp select CARDINALITY(ARRAY[TRUE, TRUE, FALSE]) from source_stream;

HELLO WORLD is returned.

insert into temp select ELEMENT(ARRAY['HELLO WORLD']) from source_stream;

**Table 2** Attribute access functions
Function	Return Data Type	Description
tableName.compositeType.field	-	Select a single field, use the name to access the field of Apache Flink composite types, such as Tuple and POJO, and return the value.
tableName.compositeType.*	-	Select all fields, and convert Apache Flink composite types, such as Tuple and POJO, and all their direct subtypes into a simple table. Each subtype is a separate field.