Using the ESCAPE Option of the LIKE Operator

If you really want to search for actual percent sign or underscore characters with the LIKE operator, you need to suppress the special meaning of those characters. You can do this with the ESCAPE option of the LIKE operator, as demonstrated here:

SQL> select empno, begindate, comments
2 from history
3 where comments like '%0\%%' escape '\';
EMPNO BEGINDATE COMMENTS
-------- ----------- ----------------------------------------------------
7566 01-JUN-1989 From accounting to human resources; 0% salary change
7788 15-APR-1985 Transfer to human resources; 0% salary raise
SQL>

The WHERE clause here searches for 0% in the COMMENTS column of the HISTORY table. The backslash (\) suppresses the special meaning of the second percent sign in the search string. Note that you can pick a character other than the backslash to use as the ESCAPE character.