mysql数据库for循环语句

DELIMITER //

CREATE PROCEDURE loop_example()
BEGIN
  DECLARE counter INT DEFAULT 1;
  
  my_loop: LOOP
    -- 循环逻辑
    
    SET counter = counter + 1;
    IF counter > 10 THEN
      LEAVE my_loop;
    END IF;
  END LOOP my_loop;
  
END //

DELIMITER ;

DELIMITER //

CREATE PROCEDURE loop_example()
BEGIN
  DECLARE done INT DEFAULT FALSE;
  DECLARE value INT;
  
  -- 创建游标
  DECLARE cursor_name CURSOR FOR SELECT column_name FROM table_name;
  
  -- 异常处理
  DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
  
  -- 打开游标
  OPEN cursor_name;
  
  -- 循环遍历结果集
  my_loop: LOOP
    FETCH cursor_name INTO value;
    
    IF done THEN
      LEAVE my_loop;
    END IF;
    
    -- 循环逻辑
    
  END LOOP my_loop;
  
  -- 关闭游标
  CLOSE cursor_name;
  
END //

DELIMITER ;