RULES OF PRIORITY

IN SQL SELECT statement the oracle server evaluates comparison operator’s begor logival operators.

In the evaluation of logical operators ,NOT is evaluated first,AND is evaluated second,and OR

Is evaluated third.

You can override rules of precedence by using parentheses.

For example

Select empno,ename,job

From  emp

Where  SAL =1500

AND (JOB  =’SALESMAN’

OR  job  =’CLERK’);

    EMPNO ENAME      JOB

--------- ---------- ---------

     7844 TURNER     SALESMAN

The result lists employees who are either a CLERK or a SALESMAN and who earn more than $1500.