mysql按字段循环

DELIMITER //

CREATE PROCEDURE process_data()
BEGIN
    DECLARE done INT DEFAULT FALSE;
    DECLARE field_value VARCHAR(255);
    DECLARE cur CURSOR FOR SELECT column_name FROM table_name;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;

    OPEN cur;

    read_loop: LOOP
        FETCH cur INTO field_value;
        IF done THEN
            LEAVE read_loop;
        END IF;

        -- 在这里对field_value进行处理
        -- 例如：UPDATE table_name SET other_column = 'new_value' WHERE column_name = field_value;
    END LOOP;

    CLOSE cur;
END //

DELIMITER ;

CALL process_data();