mysql中 循环控制语句

[begin_label:] LOOP
    SQL逻辑...
END LOOP [end_label];

DELIMITER //

CREATE PROCEDURE counter()
BEGIN
    DECLARE i INT DEFAULT 1;

    loop_label: LOOP
        SELECT i;
        SET i = i + 1;
        IF i > 5 THEN
            LEAVE loop_label;
        END IF;
    END LOOP loop_label;
END //

DELIMITER ;

[begin_label:] WHILE expression DO
    SQL逻辑...
END WHILE [end_label];

DELIMITER //

CREATE PROCEDURE counter()
BEGIN
    DECLARE i INT DEFAULT 1;

    WHILE i <= 5 DO
        SELECT i;
        SET i = i + 1;
    END WHILE;
END //

DELIMITER ;