1.Mysql update语句赋值嵌套select 点击(此处)折叠或打开 update a set col=(select col from a where id='5') where id>5 and id<10; 报错了 ERROR 1093 (HY000): You can't specify target table 'a' for update in FROM clause 经过研究 发现是 mysql 定义update语句不能同时对同一张进行set 赋值操作,也就是说 upd
Update和Select结合统计更新 update table_a set updatetime=getdate(), name=b.name from (select name,age from table_b where table_b.Id=1) as b where table_a.id=1 -- UPDATE A SET A1 = B1, A2 = B2, A3 = B3 FROM A, B WHERE A.ID = B.ID update Table_Main set DataSt
小结: 1.注意使用限制 Locking reads are only possible when autocommit is disabled (either by beginning transaction with START TRANSACTION or by setting autocommit to 0. SELECT ... FOR UPDATE or SELECT ... FOR SHARE MySQL :: MySQL 8.0 Reference Manual :: 15.7.
UPDATE `TB_CM_Dic` SET `ParentID` = (SELECT `ID` FROM (SELECT * FROM `TB_CM_Dic`) AS B WHERE `DicName` = '药品类别') WHERE `ID` = ( SELECT `ID` FROM( SELECT * FROM `TB_CM_Dic` WHERE `DicName` = '日常用品' AND `ParentID` = ( SELECT `ID` D FROM `TB_CM_Dic` D W
1. SELECT语句的子查询 语法: SELECT ... FROM (subquery) AS name ... 先创建一个表: CREATE TABLE t1 (s1 INT, s2 CHAR(5), s3 FLOAT);INSERT INTO t1 VALUES (1,'1',1.0);INSERT INTO t1 VALUES (2,'2',2.0); 我们就可以进行以下的嵌套查询了:SELECT sb1,sb2,sb3 FROM (SELECT s1 AS sb1
update或delete语句里含有子查询时,子查询里的表不能在update或是delete语句中,如含有运行时会报错:但select语句里含有子查询时,子查询里的表可以在select语句中. 如:把总成绩小于100的学生名称修改为天才 select stu_id from score group by stu_id having sum(grade)<100; #查询总成绩小于100的学生IDupdate students set name='天才' where id in (select s
原文: http://dev.mysql.com/doc/refman/5.0/en/innodb-locking-reads.html In some circumstances, a consistent (nonlocking) read is not convenient and a locking read is required instead. InnoDB supports two types of locking reads: SELECT ... LOCK IN SHARE
UPDATE fl_user_space u SET u.`course_count` = (SELECT COUNT(*) FROM fl_course c WHERE c.uid = u.uid) WHERE 1 = 1 AND u.school_id = #${schoolId}#; 这种执行效率执行时间在秒级以上,几秒到几十秒,数据量大时甚至更长 UPDATE fl_user_space u, (SELECT c.uid ,COUNT(course_id) AS course_count
本文转自:http://blog.csdn.net/disiwei1012/article/details/52589181 http://www.blogjava.net/Jhonney/archive/2010/06/25/324503.html $ sqlplus user/pass SQL*Plus: Release - Production on Wed Aug :: Copyright (c) , , Oracle Corporation. All rights reserved.