When aggregate function returns NULL value

DB2 Aggregate functions also called Column functions.

Example:

SELECT MAX(VALUE_1) FROM SAMPLES.TABLE_1;

Rules:

• All aggregate functions, we need to use only in SELECT statement
• If no row found, we will not get +100 sqlcode, instead we will get NULL value
• The return value from all Aggregate functions can be NULL, but for COUNT and COUNT_BIG always numeric result
• COUNT always return integer
• COUNT_BIG always return DECIMAL
• DISTINCT can be applied on all aggregate functions. But has no effect on MAX and MIN functions