mysql while控制结构

WHILE 条件 DO
    -- 要执行的SQL语句或代码块
END WHILE;

DELIMITER //

CREATE PROCEDURE ProcessData()
BEGIN
    DECLARE done INT DEFAULT FALSE;
    DECLARE v_id INT;
    DECLARE v_name VARCHAR(255);
    -- 假设有一个名为data_table的表，包含id和name两列
    DECLARE cur CURSOR FOR SELECT id, name FROM data_table;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;

    OPEN cur;

    read_loop: LOOP
        FETCH cur INTO v_id, v_name;
        IF done THEN
            LEAVE read_loop;
        END IF;

        -- 在这里执行对每条数据的处理逻辑
        -- 例如：更新数据、插入日志等
        UPDATE data_table SET status = 'processed' WHERE id = v_id;
    END LOOP;

    CLOSE cur;
END //

DELIMITER ;

CLOSE cur;