MySQL Tutorial/Procedure Function/Operator

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Boolean operator: NOT

mysql> delimiter $$
mysql>
mysql>
mysql> CREATE PROCEDURE myProc()
    -> BEGIN
    ->         DECLARE a INT DEFAULT 2;
    ->         DECLARE b INT DEFAULT 3;
    ->         DECLARE c FLOAT;
    ->
    ->         IF NOT (a=b) THEN
    ->                 SELECT "a is not equal to b";
    ->         END IF;
    -> END$$
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql> delimiter ;
mysql> call myProc();
+---------------------+
| a is not equal to b |
+---------------------+
| a is not equal to b |
+---------------------+
1 row in set (0.02 sec)
Query OK, 0 rows affected (0.02 sec)
mysql> drop procedure myProc;
Query OK, 0 rows affected (0.00 sec)
mysql>


Logic operator

mysql>
mysql> delimiter $$
mysql>
mysql> CREATE PROCEDURE myProc()
    -> BEGIN
    ->         DECLARE a INT DEFAULT 2;
    ->         DECLARE b INT DEFAULT 3;
    ->         DECLARE c FLOAT;
    ->
    ->         IF (a<b) THEN
    ->                 SELECT "a is less than b";
    ->         END IF;
    -> END$$
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql> delimiter ;
mysql> call myProc();
+------------------+
| a is less than b |
+------------------+
| a is less than b |
+------------------+
1 row in set (0.00 sec)
Query OK, 0 rows affected (0.02 sec)
mysql> drop procedure myProc;
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql>
mysql>
Источник — «http://sqle.ru/index.php?title=MySQL_Tutorial/Procedure_Function/Operator&oldid=725»