mysql 判断循环语句

DELIMITER //

CREATE PROCEDURE process_data()
BEGIN
    DECLARE i INT DEFAULT 1;
    DECLARE total INT;

    -- 假设有一个名为data_table的表，其中有一个名为value的字段
    SELECT COUNT(*) INTO total FROM data_table;

    WHILE i <= total DO
        -- 在这里执行你的操作，例如更新数据
        UPDATE data_table SET processed = TRUE WHERE id = i;

        SET i = i + 1;
    END WHILE;
END //

DELIMITER ;

DELIMITER //

CREATE PROCEDURE process_data_batch(batch_size INT)
BEGIN
    DECLARE i INT DEFAULT 1;
    DECLARE total INT;

    SELECT COUNT(*) INTO total FROM data_table;

    WHILE i <= total DO
        -- 批量更新数据
        UPDATE data_table SET processed = TRUE WHERE id BETWEEN i AND LEAST(i + batch_size - 1, total);

        SET i = i + batch_size;
    END WHILE;
END //

DELIMITER ;

DELIMITER //

CREATE PROCEDURE process_data_with_limit(limit INT)
BEGIN
    DECLARE i INT DEFAULT 1;
    DECLARE total INT;

    SELECT COUNT(*) INTO total FROM data_table;

    WHILE i <= total DO
        IF i > limit THEN
            LEAVE WHILE;
        END IF;

        UPDATE data_table SET processed = TRUE WHERE id = i;

        SET i = i + 1;
    END WHILE;
END //

DELIMITER ;