1.删除完全重复数据 原始数据: 期望数据: delete result from (select ROW_NUMBER () over(partition by id order by id) r, * from temp_0814  t ) result where result.r!=1 2.删除查询的前N条记录 原始数据: 期望数据: DELETE TOP (3)  FROM temp WHERE id=1

CREATE TABLE tmp AS (SELECT DISTINCT * FROM oa_organization);--将不重复的数据存入新建临时表tmp DELETE FROM oa_organization;--删除对应的表 INSERT INTO oa_organization SELECT * FROM tmp;--把临时表里的数据存入对应的表 DROP TABLE tmp;--删除临时表

  /***********************************************两个意义上的重复记录:1.是完全重复的记录,也即所有字段均重复的记录,2.是部分关键字段重复的记录,比如username字段重复,  而其他字段不一定重复或都重复可以忽略,这类重复  问题通常要求保留重复记录中的第一条记录************************************************/ /*1.数据完全重复(用到了一个临时表#Tmp)*/CREATE TABLE

oracle 快速删除大批量数据方法(全部删除,条件删除,删除大量重复记录) 分类: ORACLE 数据库 2011-05-24 16:39 8427人阅读 评论(2) 收藏 举报 oracledeletetablesqllogginginsert 全部删除 如果是删除某个表的所有数据,并且不需要回滚,使用 TRUNCATE 就ok了.关于Trancate 参见这里http://blog.csdn.net/gnolhh168/archive/2011/05/24/6442561.aspx SQL

--创建测试表 CREATE TABLE TEST ( DEPTNO ), DNAME ), LOC ) ); --插入测试数据 , 'test1', 'test2'); , 'test1', 'test2'); , 'test2', 'test3'); , 'test2', 'test3'); --查询所有记录 SELECT * FROM TEST; --查询重复的记录 SELECT * FROM TEST WHERE deptno IN( ) --查询重复记录-1条记录 SELECT * F

--处理表重复记录(查询和删除) /****************************************************************************************************************************************************** 1.Num.Name相同的重复值记录,没有大小关系只保留一条 2.Name相同,ID有大小关系时,保留大或小其中一个记录 ********************

转自: http://www.maomao365.com/?p=10564 摘要: 下文讲述MySQL数据库查询重复数据时,只保留一条数据的方法 实现思路: 在MySQL数据库中没有row_number函数,所以我们需变向实现此功能.  --1.基础数据表查看 mysql> select * from `maomao365.com`; +-------+------------+ | keyId | infoB | +-------+------------+ | mysql test | |

参考网址:http://database.51cto.com/art/201103/250046.htm SQL Server数据库多种方式查找重复记录 select * from dbo.T0058_PointObjectGIS ) select c0130_entcode,c0130_entname,COUNT(*) from T0140_EntList group by c0130_entcode,c0130_entname

delete from A_TO_NOW where yuan_name in (select   yuan_name from A_TO_NOW group by   yuan_name   having count(yuan_name) > 1) and rowid not in (select min(rowid) from   A_TO_NOW group by yuan_name having count(yuan_name )>1)

delete from people where   peopleName in (select peopleName    from people group by peopleName      having count(peopleName) > 1) and   peopleId not in (select min(peopleId) from people group by peopleName     having count(peopleName)>1)

SELECT * FROM EnterpriseDataTools.Enterprise.CompanyMainwhere CompanyNo in (select CompanyNo from EnterpriseDataTools.Enterprise.CompanyMain group by CompanyNo having count(CompanyNo) > 1)and Id not in (select max(Id) from EnterpriseDataTools.Enterpr

验证:mysql 5.6版本 方法一: delete a from table a left join( select (id) from table group by studentName,classId) b on a.id=b.id where b.id is null; 方法二: explain delete from table where id not in (select minid from (select min(id) as minid from table group b

select company ,count(company) as coun into myls from mylist group by company having count(company)>1  --讲MyList重复的数据放到myls中 declare @id int declare @company varchar(200) declare @td table(id int,address nvarchar(200),linkman nvarchar(100),tel nvarch

and not exists( and a.StateValue>StateValue ) '

要保留的数据: WITH summary AS ( SELECT p.id, p.customer, p.total, ROW_NUMBER() OVER(PARTITION BY p.customer --分组 ORDER BY p.total DESC) AS rk FROM PURCHASES p) SELECT s.* FROM summary s WHERE s.rk = 1 --1表示分组后分组结果第一行 稍微修改之后的删除: WITH summary AS ( SELECT p.i

使用Northwind 数据库 首先查询Employees表 查询结果: city列里面只有5个城市 使用ROW_NUMBER() OVER(PARTITION BY COL1 ORDER BY COL2) 先进行分组 注:根据COL1分组,在分组内部根据 COL2排序,而此函数计算的值就表示每组内部排序后的顺序编号(组内连续的唯一的). sql语句为: select EmployeeID,LastName,FirstName,Title,TitleOfCourtesy,City,ROW_NUM

网上有很多的办法,但是大多数都是通过临时表的办法,其实你是可以用一句简单的sql就可以做到: alter ignore table SOMETABLE add primary key(fields need to be deduplicate) 版权声明:本文为博主原创文章,未经博主允许不得转载.

distinct : select distinct ID from table1

select * from AM_C4_ENTRY t where t.created_by in ( select t.created_by from AM_C4_ENTRY t group by t.created_by having count(t.created_by) > 1) ;

DELETE FROM xx WHERE ROWID NOT IN (SELECT MIN(ROWID) FROM xx  GROUP BY xx, xx);

例如: id           name         value 1               a                 pp 2               a                 pp 3               b                 iii 4               b                 pp 5               b                 pp 6               c