A logical operator combines the results of two component conditions to produce a single result or to invert the result of a single condition. The following table lists the supported logical operators.

Table 1. Logical Operators
Operator Purpose Example
NOT Returns TRUE if the following condition is FALSE. Returns FALSE if it is TRUE. If it is UNKNOWN, it remains UNKNOWN. 
SELECT * FROM emp WHERE NOT (job 
IS NULL)
SELECT * FROM emp WHERE NOT (sal 
BETWEEN 1000 AND 2000)
AND Returns TRUE if both component conditions are TRUE. Returns FALSE if either is FALSE; otherwise, returns UNKNOWN. 
SELECT * FROM emp WHERE job = 
'CLERK' AND deptno = 10
OR Returns TRUE if either component condition is TRUE. Returns FALSE if both are FALSE; otherwise, returns UNKNOWN. 
SELECT * FROM emp WHERE job = 
'CLERK' OR deptno = 10

Example

In the Where clause of the following Select statement, the AND logical operator is used to ensure that managers earning more than $1000 a month are returned in the result:

SELECT * FROM emp WHERE jobtitle = manager AND sal > 1000