MySQL利用LOOP循环语句实现存储的方法教程
MySQL利用LOOP循环语句实现存储的方法教程
MySQL存储过程的语句中有三个标准的循环方式：WHILE循环，LOOP循环以及REPEAT循环。还有一种非标准的循环方式：GOTO，不过这种循环方式最好别用，很容易引起程序的混乱，在这里就不错具体介绍了。今天我们先来看看LOOP循环
mysql>
mysql> delimiter $$
mysql>
mysql> CREATE PROCEDURE myProc()
-> BEGIN
->
-> DECLARE i int;
-> SET i=0;
-> loop1: LOOP
-> SET i=i+1;
-> IF i>=10 THEN /*Last number - exit loop*/
-> LEAVE loop1;
-> ELSEIF MOD(i,2)=0 THEN /*Even number - try again*/
-> ITERATE loop1;
-> END IF;
->
-> SELECT CONCAT(i," is an odd number");
->
-> END LOOP loop1;
->
->
-> END$$
Query OK, 0 rows affected (0.02 sec)
mysql>
mysql> delimiter ;
mysql> call myProc();
+-------------------------------+
CONCAT(i," is an odd number") |
+-------------------------------+
1 is an odd number |
+-------------------------------+
1 row in set (0.00 sec)
+-------------------------------+
CONCAT(i," is an odd number") |
+-------------------------------+
3 is an odd number |
+-------------------------------+
1 row in set (0.00 sec)
+-------------------------------+
CONCAT(i," is an odd number") |
+-------------------------------+
5 is an odd number |
+-------------------------------+
1 row in set (0.00 sec)
+-------------------------------+
CONCAT(i," is an odd number") |
+-------------------------------+
7 is an odd number |
+-------------------------------+
1 row in set (0.01 sec)
+-------------------------------+
CONCAT(i," is an odd number") |
+-------------------------------+
9 is an odd number |
+-------------------------------+
1 row in set (0.01 sec)
Query OK, 0 rows affected (0.01 sec)
mysql> drop procedure myProc;
Query OK, 0 rows affected (0.00 sec)
mysql>