在mysql中,通过一张表的列修改另一张关联表中的内容: 1: 修改1列 update student s, city c set s.city_name = c.name where s.city_code = c.code; 2: 修改多个列 update a, b set a.title=b.title, a.name=b.name where a.id=b.id 3: 采用子查询 update student s set city_name = (select name from c
update CDINFO.Dept_Dict tab1 set PART_FLAG = (select PART_FLAG from DICT.DEPARTMENT_DICT@zyhis4 tab2 where tab1.dept_code = tab2.dept_code) where exists (select 1 from DICT.DEPARTMENT_DICT@zyhis4 tab2 where tab1.dept_code = tab2.dept_code)
UPDATE channelcountry, appywproducts SET channelcountry.ChannelName = appywproducts.YWNameCN WHERE channelcountry.ChannelCode = appywproducts.YWCode; 或者 UPDATE channelcountry a SET ChannelName = ( SELECT YWNameCN FROM appywproducts b WHERE a.ChannelC
知道是两张表进行更新,之前作过mysql的,直接就写了: update a,b set a.code = b.code wehre a.id = b.id 然后就报错了,上网查了下知道oracle不能这样子写 之后找到如下的办法: UPDATE a set a.code = (select b.code from b where a.id = b.id) 但是这条语句如果数据多的话会很慢,因为他要每条数据都要跟新 然后又找到了这条sql: MERGE INTO a USING b ON ( a.
1.查看删除数据库表的唯一约束 SHOW INDEX FROM tbl_name (唯一约束也是索引) ALTER TABLE tbl_name DROP INDEX index_name 2.update where中不能使用子查询,解决方案如下: 将子查询作为一张表放在前面 UPDATE `areainfo` a, ( SELECT code FROM `areainfo` where level = 1 ) b SET a.`level` =2 WHERE a.`parent_code
一.去重 1.查询出重复的记录 CREATE TABLE push_log_full_2013_10_30_tmp SELECT * FROM `push_log_full` WHERE time BETWEEN FROM_DAYS(TO_DAYS(NOW()) - 1) AND FROM_DAYS(TO_DAYS(NOW())) AND (imsi, andriodid, time) IN ( SELECT imsi, andriodid, time FROM `push_log_full`
工作中遇到两表查询,从user表中获取用户唯一id字段 写入到另外一张qiuzu表中的uid字段中; 二者可以关联起来的只有用户的手机号码tel字段; 了解需求后数据量稍多,不可能一个一个的手动修改 最快的只有通过mysql语句来解决问题了 使用左联接 UPDATE qiuzu q LEFT JOIN USER u ON q.tel = u.tel SET q.uid = u.id WHERE q.uid IS NULL OR q.uid = 0 仅作工作记录只用(http://www.hioo