MySQL มี IF() สำหรับ SELECT และ IF ... THEN ... ELSE ... END IF สำหรับ Stored Procedure
IF() ในคำสั่ง SELECT
mysql> select if(0=0,'Hello MySQL','condition is wrong');
+------------------------------------------------------+
| if('test'='test','Hello MySQL','condition is wrong') |
+------------------------------------------------------+
| Hello MySQL |
+------------------------------------------------------+
mysql> select if(1=0,'Hello MySQL','condition is wrong');
+--------------------------------------------+ | if(1=0,'Hello MySQL','condition is wrong') | +--------------------------------------------+ | condition is wrong | +--------------------------------------------+
IF ใน Stored Procedure
mysql> DELIMITER //
mysql> CREATE PROCEDURE if_demo(value int)
BEGIN
IF 1=value THEN
SELECT "Hello MySQL";
ELSE
SELECT "Wrong Condition";
END IF;
END
//
Query OK, 0 rows affected (0.20 sec)
mysql> DELIMITER ;
เรียกใช้ Procedure
mysql> call if_demo(1);
+-------------+ | Hello MySQL | +-------------+ | Hello MySQL | +-------------+
mysql> call if_demo(0);
+-----------------+ | Wrong Condition | +-----------------+ | Wrong Condition | +-----------------+
