mysql怎么循环查询

SELECT 
    u.id, 
    u.name, 
    (SELECT COUNT(*) FROM orders o WHERE o.user_id = u.id) AS order_count
FROM 
    users u;

DELIMITER //

CREATE PROCEDURE UpdateUserPoints()
BEGIN
    DECLARE done INT DEFAULT FALSE;
    DECLARE userId INT;
    DECLARE points INT;
    DECLARE cur CURSOR FOR SELECT id, points FROM users;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;

    OPEN cur;

    read_loop: LOOP
        FETCH cur INTO userId, points;
        IF done THEN
            LEAVE read_loop;
        END IF;

        -- 假设我们要给每个用户增加10积分
        UPDATE users SET points = points + 10 WHERE id = userId;
    END LOOP;

    CLOSE cur;
END //

DELIMITER ;

UPDATE users 
SET points = points + 10;