mysql怎么遍历数据库里的数据

SELECT * FROM table_name;

DECLARE cursor_name CURSOR FOR SELECT * FROM table_name;
OPEN cursor_name;

FETCH cursor_name INTO variable1, variable2, ...;
WHILE (FOUND_ROWS() > 0) DO
    -- 处理数据
    FETCH cursor_name INTO variable1, variable2, ...;
END WHILE;

CLOSE cursor_name;

CREATE PROCEDURE procedure_name()
BEGIN
    DECLARE done INT DEFAULT 0;
    DECLARE variable1, variable2, ...;
    DECLARE cursor_name CURSOR FOR SELECT * FROM table_name;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;

    OPEN cursor_name;

    my_loop: LOOP
        FETCH cursor_name INTO variable1, variable2, ...;
        IF done = 1 THEN
            LEAVE my_loop;
        END IF;

        -- 处理数据
    END LOOP;

    CLOSE cursor_name;
END;