mysql实例 while循环中的if语句

1，while循环中使用if分支语句
代码：

mysql>
mysql> delimiter $$
mysql>
mysql> CREATE PROCEDURE myProc() //创建while循环的存储过程 if分支语句示例
    -> BEGIN
    ->
    ->     DECLARE i int;
    ->     SET i=1;
    ->     loop1: WHILE i<=10 DO
    ->          IF MOD(i,2)<>0 THEN /*Even number - try again*/
    ->             SELECT CONCAT(i," is an odd number");
    ->          END IF;
    ->          SET i=i+1;
    ->     END WHILE loop1;
    -> END$$
Query OK, 0 rows affected (0.00 sec)

mysql>
mysql> delimiter ;
mysql> call myProc(); //调用存储过程
+-------------------------------+
| CONCAT(i," is an odd number") |
+-------------------------------+
| 1 is an odd number            |
+-------------------------------+
1 row in set (0.02 sec)

+-------------------------------+
| CONCAT(i," is an odd number") |
+-------------------------------+
| 3 is an odd number            |
+-------------------------------+
1 row in set (0.02 sec)

+-------------------------------+
| CONCAT(i," is an odd number") |
+-------------------------------+
| 5 is an odd number            |
+-------------------------------+
1 row in set (0.02 sec)

+-------------------------------+
| CONCAT(i," is an odd number") |
+-------------------------------+
| 7 is an odd number            |
+-------------------------------+
1 row in set (0.02 sec)

+-------------------------------+
| CONCAT(i," is an odd number") |
+-------------------------------+
| 9 is an odd number            |
+-------------------------------+
1 row in set (0.02 sec)

Query OK, 0 rows affected (0.38 sec)

mysql> drop procedure myProc;
Query OK, 0 rows affected (0.00 sec)

2，带label标签的while循环
代码：

DELIMITER $$

CREATE PROCEDURE AGAIN
   (OUT RESULT INTEGER)
BEGIN
   DECLARE COUNTER INTEGER DEFAULT 1;
   SET RESULT = 0;
   LOOP1: WHILE COUNTER <= 1000 DO
      SET COUNTER = COUNTER + 1;
      IF COUNTER > 100 THEN
         LEAVE LOOP1;
      ELSE
         ITERATE LOOP1;
      END IF;
      SET RESULT = COUNTER * 10;
   END WHILE LOOP1;
END$$

DELIMITER ;