UPDATE和SELECT嵌套使用

1 2 update a set HIGH=b.NEW from SPEC1 a,tmpDOT b where a.high=b.old…

Mysql update语句赋值嵌套与在表列中数据后面增加数据

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…

select * from salgrade for update和select * from salgrade for update nowait区别

1,select * from salgrade for update session1 session2 SQL> delete salgrade where grade=1; 1 row deleted. SQL> select * from salgrade for update; 此时session2被阻塞 SQL> rollback; Rollback complete. GRADE LOSAL HISAL ----------…

浅谈select for update 和select lock in share mode的区别

有些情况下为了保证数据逻辑的一致性,需要对SELECT的操作加锁.InnoDB存储引擎对于SELECT语句支持两种一致性的锁定读(locking read)操作. . SELECT …… FOR UPDATE . SELECT …… LOCK IN SHARE MODE 其中,SELECT …… FOR UPDATE对读取的记录加一个锁,其他事务不能对已锁定的行加任何锁.而SELECT …… LOCK IN SHARE MODE也是对读取的记录加一个锁. 但是如果有另一个一致性非锁定读的操作来读…

select for update和select for update wait和select for update nowait的区别

CREATE TABLE "TEST6" ( "ID" ), "NAME" ), "AGE" ,), "SEX" ), "ENAME" ), "ADDTIME" DATE ) , null, 'zhangsan', to_date('14-03-2017 00:00:09', 'dd-mm-yyyy hh24:mi:ss')); ', 'Lisi', to_date(…

Update和Select结合统计更新

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…

SELECT ... FOR UPDATE or SELECT ... FOR SHARE Locking Reads session

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.…

Oracle update和select 关联

Oracle update和select 关联目录 Oracle update和select 关联 1.介绍 2.解决方法 2.1.需求 2.2.错误演示 2.3.解决方法 1.介绍本文主要向大家介绍了Oracle数据库之oracle update set select from 关联更新,通过具体的内容向大家展现,希望对大家学习Oracle数据库有所帮助. 工作中有个需求,现在新表中有一些数据跟老表的基本一样,这样只需要把老表中数据搬到新表中就可以了,同时把不同的字段修改下数据即可,在修改…

MySql Update Select 嵌套

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…

select 嵌套查询

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…

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