SQL用select语句查询重复记录
SQL用select语句查询重复记录
http://hi.baidu.com/bilbit/blog/item/5ed5de16a6f6b412962b43eb.html
用select语句,查询重复记录
假设,表名为 T1 子段为 A,B,C
select count(*) ,A,B,C from T1
group by A,B,C having count(*) > 1
测试数据:
A100 B100 C100
A101 B101 C101
A102 B102 C102
A102 B102 C100
A102 B102 C102
A102 B102 C102
A100 B100 C100
运行结果:
2 A100 B100 C100
3 A102 B102 C102
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选择重复,消除重复和选择出序列
有例表:emp
emp_no name age &nbs
相关文档:
数据字典dict总是属于Oracle用户sys的。
1、用户:
select username from dba_users;
改口令
alter user spgroup identified by spgtest;
2、表空间:
select * from dba_data_files;
select * from dba_tablespaces;//表空间
select tablespace_name,sum(bytes), sum(b ......
declare @XML XML
SET @XML='<root>
<OLDVALUE>
<H_Action id="1130">030</H_Action>
<D_Action>030</D_Action>
<OrderCompany>00220</OrderCompany>
<OrderNumber>10004035</OrderNumber> ......
一、基础
1、说明:创建数据库
CREATE DATABASE database-name
2、说明:删除数据库
drop database dbname
3、说明:备份sql server
--- 创建 备份数据的 device
USE master
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat'
--- 开始 备份
BACKUP DATABASE pubs TO testBack
4、说 ......
一、基础
1、说明:创建数据库
CREATE DATABASE database-name
2、说明:删除数据库
drop database dbname
3、说明:备份sql server
--- 创建 备份数据的 device
USE master
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat'
--- 开始 备份
BACKUP DATABASE pubs TO testBack
4、说 ......
SQL查询重复记录
http://m.cnblogs.com/15628/1534873.html
1、查找表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断
[图片]select * from people
[图片]where peopleId in (select peopleId from people group by peopleId ......