Show TOC

Null predicateLocate this document in the navigation structure

The null predicate is used to test if a column contains a NULL value.

Syntax 

<null predicate> ::= 
                            <column reference> IS ( NOT )? NULL.

The <null predicate> "colref IS NOT NULL" is equivalent to the <boolean factor> "NOT colref IS NULL".

The result of the <null predicate> "colref IS NULL" is true if the value of the <column reference> colref is the NULL value, otherwise the result of the <null predicate> is false.

Example 

SELECT * FROM a WHERE c IS NOT NULL

The IS NULL Predicate . This query yields all rows from table a where the column a.c is not the NULL value.

More Information

Column References