Oracle's SQL statement, query condition parentheses and no parentheses-

Source: Internet
Author: User

For example:

SELECT ename, Job, Deptno
From EMP
WHERE Deptno in (10, 20)
and (ename like '%I ' or job like '%er ');

Execute the SQL with the result set as follows:
1 JONES MANAGER 20
2 CLARK MANAGER 10

Remove the parentheses in the SQL query criteria above,
SELECT ename, Job, Deptno
From EMP
WHERE Deptno in (10, 20)
and ename like '%I ' or job like '%er ';

The result set is as follows:
1 JONES MANAGER 20
2 BLAKE MANAGER 30
3 CLARK MANAGER 10

The reason for the difference is that the and is higher than or priority, and the parentheses can change the priority of the condition judgment!!!!!!!

Oracle's SQL statement, query condition parentheses and no parentheses-

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