这里的ITERATE(迭代)让循环又回到了循环的头部。
ITERATE: walking through the loop
CREATE PROCEDURE p20 ()
BEGIN
DECLARE v INT;
SET v = 0;
loop_label: LOOP
IF v = 3 THEN
SET v = v + 1;
ITERATE loop_label;
END IF;
INSERT INTO t VALUES (v);
SET v = v + 1;
IF v >= 5 THEN
LEAVE loop_label; <--
END IF;
END LOOP;
END; // 当v的值变为5时,程序将执行LEAVE语句
ITERATE: walking through the loop
CREATE PROCEDURE p20 ()
BEGIN
DECLARE v INT;
SET v = 0;
loop_label: LOOP
IF v = 3 THEN
SET v = v + 1;
ITERATE loop_label;
END IF;
INSERT INTO t VALUES (v);
SET v = v + 1;
IF v >= 5 THEN
LEAVE loop_label;
END IF;
END LOOP;
END; // <--
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