MySQL Replace function throwing error
That's odd, When I run your statements on 5.5 I get a syntax error:

mysql&gt; CREATE TABLE TEST(COLA INT,DESCRIPTION VARCHAR(20));
Query OK, 0 rows affected (0.02 sec)

mysql&gt; UPDATE TEST 
    -&gt; SET DESCRIPTION=REPLACE(DESCRIPTION,CHAR(92),CHAR(7)) 
    -&gt; WHERE DESCRIPTION like '%' CHAR(07) '%';
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual
that corresponds to your MySQL server version for the right syntax to use
near 'CHAR(07) '%'' at line 3


Anyway, the proper way to do what you want to achieve would be concatenating '%' and the \G, that is:

UPDATE TEST 
SET DESCRIPTION=REPLACE(DESCRIPTION,CHAR(92),CHAR(7)) 
WHERE DESCRIPTION like CONCAT('%',CHAR(07),'%');