CARDINALITY Function in Oracle SQL – PLSQL

Oracle SQL / PLSQL CARDINALITY function is used to return the number of elements in a nested table.

Oracle SQL / PLSQL syntax for the CARDINALITY function is:

SELECT CARDINALITY (nested_column)
FROM table_name;

nested_column is the column in the nested table whose CARDINALITY we want to determine.

If nested table is empty or is a NULL collection then CARDINALITY function in Oracle SQL / PLSQL will return NULL.

Using Oracle SQL Cardinality Function with SELECT Statement

SELECT employee_id
       ,CARDINALITY(location)
FROM employee;

The example above shows the use of Oracle SQL Cardinality Function with SQL SELCt Statement.