CARDINALITY Function

The CARDINALITY function returns the number of elements in a collection column (SET, MULTISET, LIST).

The CARDINALITY function has the following syntax.
CARDINALITY Function

1  CARDINALITY  (
2.1 collection_col
2.1 collection_var
1 )
Element Description Restrictions Syntax
collection_col An existing collection column Must be declared as a collection data type Identifier
collection_var Host or program collection variable Must be declared as a collection data type Language specific
Suppose that the set_col SET column contains the following value: 
{3, 7, 9, 16, 0}
The following SELECT statement returns 5 as the number of elements in the set_col column: 
SELECT CARDINALITY(set_col)
   FROM table1;

If the collection contains duplicate elements, CARDINALITY counts each individual element.