mysql循环语句写法

DELIMITER //

CREATE PROCEDURE simple_loop()
BEGIN
    DECLARE counter INT DEFAULT 1;
    
    loop_label: LOOP
        -- 循环体内的代码
        SELECT counter;
        
        SET counter = counter + 1;
        
        -- 当counter大于5时退出循环
        IF counter > 5 THEN
            LEAVE loop_label;
        END IF;
    END LOOP loop_label;
END //

DELIMITER ;

DELIMITER //

CREATE PROCEDURE while_loop()
BEGIN
    DECLARE counter INT DEFAULT 1;
    
    WHILE counter <= 5 DO
        -- 循环体内的代码
        SELECT counter;
        
        SET counter = counter + 1;
    END WHILE;
END //

DELIMITER ;

DELIMITER //

CREATE PROCEDURE repeat_loop()
BEGIN
    DECLARE counter INT DEFAULT 1;
    
    REPEAT
        -- 循环体内的代码
        SELECT counter;
        
        SET counter = counter + 1;
    UNTIL counter > 5 END REPEAT;
END //

DELIMITER ;