There is no double equal sign concept. It can be used to compare two values. If you use double equal sign(==) in MySQL, you will get an error message.
Let us verify the concept is true or not. Declare a variable −
mysql> set @Number=10; Query OK, 0 rows affected (0.00 sec)
Now, compare the above variable value with 10. If both the values are same then the result will be 1 otherwise 0.
Using double equal sign −
mysql> select 10==@Number;
This will produce the following output i.e. an error −
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 '==@Number' at line 1
Let us now change the double equal sign(==) to single equal sign(=) −
mysql> select 10=@Number;
This will produce the following output −
+------------+ | 10=@Number | +------------+ | 1 | +------------+ 1 row in set (0.00 sec)