以下是在 MySQL 預存程序中使用 FOR LOOP 的語法 -
delimiter // CREATE procedure yourProcedureName() wholeblock:BEGIN DECLARE anyVariableName1 INT ; Declare anyVariableName3 int; DECLARE anyVariableName2 VARCHAR(255); SET anyVariableName1 =1 ; SET anyVariableName3 =10; SET anyVariableName2 = ''; loop_label: FORLOOP IF anyVariableName1 > anyVariableName3 THEN LEAVE loop_label; END IF; SET anyVariableName2 = CONCAT(anyVariableName2 ,anyVariableName1 ,','); SET anyVariableName1 = anyVariableName1 + 1; ITERATE loop_label; END FORLOOP; SELECT anyVariableName2; END //
現在你可以實作上面的語法了。 for循環查詢如下 -
mysql> delimiter // mysql> CREATE procedure ForLoop() -> wholeblock:BEGIN -> DECLARE start INT ; -> Declare maxLimit int; -> DECLARE result VARCHAR(255); -> SET start =1 ; -> SET maxLimit=10; -> SET result = ''; -> loop_label: LOOP -> IF start > 10 THEN -> LEAVE loop_label; -> END IF; -> SET result = CONCAT(result,start,','); -> SET start = start + 1; -> ITERATE loop_label; -> END LOOP; -> SELECT result; -> END -> // Query OK, 0 rows affected (0.37 sec) mysql> delimiter ;
上面的 for 迴圈列印 1 到 10,即採用以下形式 1,2,3,4,.....10。呼叫儲存的 使用 CALL 指令的過程。語法如下 -
call yourStoredProcedureName();
呼叫的查詢如下 -
mysql> call ForLoop();
+-----------------------+ | result | +-----------------------+ | 1,2,3,4,5,6,7,8,9,10, | +-----------------------+ 1 row in set (0.00 sec) Query OK, 0 rows affected (0.01 sec)
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