需求:

根据同一表的某条件更新字段

情况一: 以group by 作为条件的

select user a, (select count(*) as tj_num, s_id from user group by s_id) b set a.tuijian_num=b.tj_num where a.id=b.s_id;

情况二: 不能以group by 作为条件的

#调用方法：call proc_update_team_info();DELIMITER ;;CREATE  PROCEDURE `proc_update_team_info`()BEGIN       DECLARE done tinyint default 0;    DECLARE uid int(11);    DECLARE team_num int DEFAULT 0;    DECLARE user_tree text DEFAULT '';    DECLARE cs CURSOR FOR SELECT id FROM `user` order by id asc;    DECLARE continue handler for sqlstate '02000' set done=1;    open cs;    while done<>1 do    fetch cs into uid;        select CONCAT(s_tree,id,',%') INTO user_tree  from `user` where id=uid;        select user_tree;        select if(count(*) is null,0,count(*)) into team_num  from `user` where s_tree like(user_tree);        update `user` set team_num=team_num where id=uid;    end while;    close cs;   END;;DELIMITER ;