SqlServer 删除重复数据保留最大id的SQL语句

多种方法：

 1 --1、用于查询重复处理记录(如果列没有大小关系时2000用生成自增列和临时表处理,SQL2005用row_number函数处理)
 2  
 3 --II、Name相同ID最大的记录,与min相反:
 4 方法1:
 5 Select * from #T a where not exists(select 1 from #T where Name=a.Name and ID>a.ID)
 6  
 7 方法2:
 8 select a.* from #T a join (select max(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID order by ID
 9  
10 方法3:
11 select * from #T a where ID=(select max(ID) from #T where Name=a.Name) order by ID
12  
13 方法4:
14 select a.* from #T a join #T b on a.Name=b.Name and a.ID<=b.ID group by a.ID,a.Name,a.Memo having count(1)=1 
15  
16 方法5:
17 select * from #T a group by ID,Name,Memo having ID=(select max(ID)from #T where Name=a.Name)
18  
19 方法6:
20 select * from #T a where (select count(1) from #T where Name=a.Name and ID>a.ID)=0
21  
22 方法7:
23 select * from #T a where ID=(select top 1 ID from #T where Name=a.name order by ID desc)
24  
25 方法8:
26 select * from #T a where ID!<all(select ID from #T where Name=a.Name)
27  
28 方法9(注:ID为唯一时可用):
29 select * from #T a where ID in(select max(ID) from #T group by Name)
30  
31 --SQL2005:
32  
33 方法10:
34 select ID,Name,Memo from (select *,max(ID)over(partition by Name) as MinID from #T a)T where ID=MinID
35  
36 方法11:
37 select ID,Name,Memo from (select *,row_number()over(partition by Name order by ID desc) as MinID from #T a)T where MinID=1
38  
39 生成结果2:
40 /*
41 ID          Name Memo
42 ----------- ---- ----
43 3           A    A3
44 5           B    B2
45  
46 (2 行受影响)
47 */
48  
49 
50 --2、删除重复记录有大小关系时,保留大的其中一个记录
51 --II、Name相同ID保留最大的一条记录:
52  
53 方法1:
54 delete a from #T a where  exists(select 1 from #T where Name=a.Name and ID>a.ID)
55  
56 方法2:
57 delete a  from #T a left join (select max(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID where b.Id is null
58  
59 方法3:
60 delete a from #T a where ID not in (select max(ID) from #T where Name=a.Name)
61  
62 方法4(注:ID为唯一时可用):
63 delete a from #T a where ID not in(select max(ID)from #T group by Name)
64  
65 方法5:
66 delete a from #T a where (select count(1) from #T where Name=a.Name and ID>a.ID)>0
67  
68 方法6:
69 delete a from #T a where ID<>(select top 1 ID from #T where Name=a.name order by ID desc)
70  
71 方法7:
72 delete a from #T a where ID<any(select ID from #T where Name=a.Name)
73  
74  
75 select * from #T
76 /*
77 ID          Name Memo
78 ----------- ---- ----
79 3           A    A3
80 5           B    B2
81  
82 (2 行受影响)
83 */

--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
整理人：中国风(Roy)
 
日期:2008.06.06
******************************************************************************************************************************************************/
 
--1、用于查询重复处理记录(如果列没有大小关系时2000用生成自增列和临时表处理,SQL2005用row_number函数处理)
 
--> --> (Roy)生成測試數據
  
if not object_id('Tempdb..#T') is null
    drop table #T
Go
Create table #T([ID] int,[Name] nvarchar(1),[Memo] nvarchar(2))
Insert #T
select 1,N'A',N'A1' union all
select 2,N'A',N'A2' union all
select 3,N'A',N'A3' union all
select 4,N'B',N'B1' union all
select 5,N'B',N'B2'
Go
 
 
--I、Name相同ID最小的记录(推荐用1,2,3),方法3在SQl05时，效率高于1、2
方法1:
Select * from #T a where not exists(select 1 from #T where Name=a.Name and ID<a.ID)
 
方法2:
select a.* from #T a join (select min(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID
 
方法3:
select * from #T a where ID=(select min(ID) from #T where Name=a.Name)
 
方法4:
select a.* from #T a join #T b on a.Name=b.Name and a.ID>=b.ID group by a.ID,a.Name,a.Memo having count(1)=1 
 
方法5:
select * from #T a group by ID,Name,Memo having ID=(select min(ID)from #T where Name=a.Name)
 
方法6:
select * from #T a where (select count(1) from #T where Name=a.Name and ID<a.ID)=0
 
方法7:
select * from #T a where ID=(select top 1 ID from #T where Name=a.name order by ID)
 
方法8:
select * from #T a where ID!>all(select ID from #T where Name=a.Name)
 
方法9(注:ID为唯一时可用):
select * from #T a where ID in(select min(ID) from #T group by Name)
 
--SQL2005:
 
方法10:
select ID,Name,Memo from (select *,min(ID)over(partition by Name) as MinID from #T a)T where ID=MinID
 
方法11:
 
select ID,Name,Memo from (select *,row_number()over(partition by Name order by ID) as MinID from #T a)T where MinID=1
 
生成结果:
/*
ID          Name Memo
----------- ---- ----
1           A    A1
4           B    B1
 
(2 行受影响)
*/



--2、删除重复记录有大小关系时,保留其中最小的一个记录 
 
--> --> (Roy)生成測試數據
 
if not object_id('Tempdb..#T') is null
    drop table #T
Go
Create table #T([ID] int,[Name] nvarchar(1),[Memo] nvarchar(2))
Insert #T
select 1,N'A',N'A1' union all
select 2,N'A',N'A2' union all
select 3,N'A',N'A3' union all
select 4,N'B',N'B1' union all
select 5,N'B',N'B2'
Go
 
--I、Name相同ID最小的记录(推荐用1,2,3),保留最小一条
方法1:
delete a from #T a where  exists(select 1 from #T where Name=a.Name and ID<a.ID)
 
方法2:
delete a  from #T a left join (select min(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID where b.Id is null
 
方法3:
delete a from #T a where ID not in (select min(ID) from #T where Name=a.Name)
 
方法4(注:ID为唯一时可用):
delete a from #T a where ID not in(select min(ID)from #T group by Name)
 
方法5:
delete a from #T a where (select count(1) from #T where Name=a.Name and ID<a.ID)>0
 
方法6:
delete a from #T a where ID<>(select top 1 ID from #T where Name=a.name order by ID)
 
方法7:
delete a from #T a where ID>any(select ID from #T where Name=a.Name)
 
 
 
select * from #T
 
生成结果:
/*
ID          Name Memo
----------- ---- ----
1           A    A1
4           B    B1
 
(2 行受影响)
*/

--3、删除重复记录没有大小关系时，处理重复值
 
 
--> --> (Roy)生成測試數據
  
if not object_id('Tempdb..#T') is null
    drop table #T
Go
Create table #T([Num] int,[Name] nvarchar(1))
Insert #T
select 1,N'A' union all
select 1,N'A' union all
select 1,N'A' union all
select 2,N'B' union all
select 2,N'B'
Go
 
方法1:
if object_id('Tempdb..#') is not null
    drop table #
Select distinct * into # from #T--排除重复记录结果集生成临时表#
 
truncate table #T--清空表
 
insert #T select * from #    --把临时表#插入到表#T中
 
--查看结果
select * from #T
 
/*
Num         Name
----------- ----
1           A
2           B
 
(2 行受影响)
*/
 
--重新执行测试数据后用方法2
方法2:
 
alter table #T add ID int identity--新增标识列
go
delete a from  #T a where  exists(select 1 from #T where Num=a.Num and Name=a.Name and ID>a.ID)--只保留一条记录
go
alter table #T drop column ID--删除标识列
 
--查看结果
select * from #T
 
/*
Num         Name
----------- ----
1           A
2           B
 
(2 行受影响)
 
*/
 
--重新执行测试数据后用方法3
方法3:
declare Roy_Cursor cursor local for
select count(1)-1,Num,Name from #T group by Num,Name having count(1)>1
declare @con int,@Num int,@Name nvarchar(1)
open Roy_Cursor
fetch next from Roy_Cursor into @con,@Num,@Name
while @@Fetch_status=0
begin 
    set rowcount @con;
    delete #T where Num=@Num and Name=@Name
    set rowcount 0;
    fetch next from Roy_Cursor into @con,@Num,@Name
end
close Roy_Cursor
deallocate Roy_Cursor
 
--查看结果
select * from #T
/*
Num         Name
----------- ----
1           A
2           B
 
(2 行受影响)
*/

---------------------完整代码（折叠）----------------------

  1 --处理表重复记录(查询和删除)
  2 /******************************************************************************************************************************************************
  3 1、Num、Name相同的重复值记录,没有大小关系只保留一条
  4 2、Name相同,ID有大小关系时,保留大或小其中一个记录
  5 整理人：中国风(Roy)
  6  
  7 日期:2008.06.06
  8 ******************************************************************************************************************************************************/
  9  
 10 --1、用于查询重复处理记录(如果列没有大小关系时2000用生成自增列和临时表处理,SQL2005用row_number函数处理)
 11  
 12 --> --> (Roy)生成測試數據
 13   
 14 if not object_id('Tempdb..#T') is null
 15     drop table #T
 16 Go
 17 Create table #T([ID] int,[Name] nvarchar(1),[Memo] nvarchar(2))
 18 Insert #T
 19 select 1,N'A',N'A1' union all
 20 select 2,N'A',N'A2' union all
 21 select 3,N'A',N'A3' union all
 22 select 4,N'B',N'B1' union all
 23 select 5,N'B',N'B2'
 24 Go
 25  
 26  
 27 --I、Name相同ID最小的记录(推荐用1,2,3),方法3在SQl05时，效率高于1、2
 28 方法1:
 29 Select * from #T a where not exists(select 1 from #T where Name=a.Name and ID<a.ID)
 30  
 31 方法2:
 32 select a.* from #T a join (select min(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID
 33  
 34 方法3:
 35 select * from #T a where ID=(select min(ID) from #T where Name=a.Name)
 36  
 37 方法4:
 38 select a.* from #T a join #T b on a.Name=b.Name and a.ID>=b.ID group by a.ID,a.Name,a.Memo having count(1)=1 
 39  
 40 方法5:
 41 select * from #T a group by ID,Name,Memo having ID=(select min(ID)from #T where Name=a.Name)
 42  
 43 方法6:
 44 select * from #T a where (select count(1) from #T where Name=a.Name and ID<a.ID)=0
 45  
 46 方法7:
 47 select * from #T a where ID=(select top 1 ID from #T where Name=a.name order by ID)
 48  
 49 方法8:
 50 select * from #T a where ID!>all(select ID from #T where Name=a.Name)
 51  
 52 方法9(注:ID为唯一时可用):
 53 select * from #T a where ID in(select min(ID) from #T group by Name)
 54  
 55 --SQL2005:
 56  
 57 方法10:
 58 select ID,Name,Memo from (select *,min(ID)over(partition by Name) as MinID from #T a)T where ID=MinID
 59  
 60 方法11:
 61  
 62 select ID,Name,Memo from (select *,row_number()over(partition by Name order by ID) as MinID from #T a)T where MinID=1
 63  
 64 生成结果:
 65 /*
 66 ID          Name Memo
 67 ----------- ---- ----
 68 1           A    A1
 69 4           B    B1
 70  
 71 (2 行受影响)
 72 */
 73  
 74  
 75 --II、Name相同ID最大的记录,与min相反:
 76 方法1:
 77 Select * from #T a where not exists(select 1 from #T where Name=a.Name and ID>a.ID)
 78  
 79 方法2:
 80 select a.* from #T a join (select max(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID order by ID
 81  
 82 方法3:
 83 select * from #T a where ID=(select max(ID) from #T where Name=a.Name) order by ID
 84  
 85 方法4:
 86 select a.* from #T a join #T b on a.Name=b.Name and a.ID<=b.ID group by a.ID,a.Name,a.Memo having count(1)=1 
 87  
 88 方法5:
 89 select * from #T a group by ID,Name,Memo having ID=(select max(ID)from #T where Name=a.Name)
 90  
 91 方法6:
 92 select * from #T a where (select count(1) from #T where Name=a.Name and ID>a.ID)=0
 93  
 94 方法7:
 95 select * from #T a where ID=(select top 1 ID from #T where Name=a.name order by ID desc)
 96  
 97 方法8:
 98 select * from #T a where ID!<all(select ID from #T where Name=a.Name)
 99  
100 方法9(注:ID为唯一时可用):
101 select * from #T a where ID in(select max(ID) from #T group by Name)
102  
103 --SQL2005:
104  
105 方法10:
106 select ID,Name,Memo from (select *,max(ID)over(partition by Name) as MinID from #T a)T where ID=MinID
107  
108 方法11:
109 select ID,Name,Memo from (select *,row_number()over(partition by Name order by ID desc) as MinID from #T a)T where MinID=1
110  
111 生成结果2:
112 /*
113 ID          Name Memo
114 ----------- ---- ----
115 3           A    A3
116 5           B    B2
117  
118 (2 行受影响)
119 */
120  
121  
122  
123 --2、删除重复记录有大小关系时,保留大或小其中一个记录
124  
125  
126 --> --> (Roy)生成測試數據
127  
128 if not object_id('Tempdb..#T') is null
129     drop table #T
130 Go
131 Create table #T([ID] int,[Name] nvarchar(1),[Memo] nvarchar(2))
132 Insert #T
133 select 1,N'A',N'A1' union all
134 select 2,N'A',N'A2' union all
135 select 3,N'A',N'A3' union all
136 select 4,N'B',N'B1' union all
137 select 5,N'B',N'B2'
138 Go
139  
140 --I、Name相同ID最小的记录(推荐用1,2,3),保留最小一条
141 方法1:
142 delete a from #T a where  exists(select 1 from #T where Name=a.Name and ID<a.ID)
143  
144 方法2:
145 delete a  from #T a left join (select min(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID where b.Id is null
146  
147 方法3:
148 delete a from #T a where ID not in (select min(ID) from #T where Name=a.Name)
149  
150 方法4(注:ID为唯一时可用):
151 delete a from #T a where ID not in(select min(ID)from #T group by Name)
152  
153 方法5:
154 delete a from #T a where (select count(1) from #T where Name=a.Name and ID<a.ID)>0
155  
156 方法6:
157 delete a from #T a where ID<>(select top 1 ID from #T where Name=a.name order by ID)
158  
159 方法7:
160 delete a from #T a where ID>any(select ID from #T where Name=a.Name)
161  
162  
163  
164 select * from #T
165  
166 生成结果:
167 /*
168 ID          Name Memo
169 ----------- ---- ----
170 1           A    A1
171 4           B    B1
172  
173 (2 行受影响)
174 */
175  
176  
177 --II、Name相同ID保留最大的一条记录:
178  
179 方法1:
180 delete a from #T a where  exists(select 1 from #T where Name=a.Name and ID>a.ID)
181  
182 方法2:
183 delete a  from #T a left join (select max(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID where b.Id is null
184  
185 方法3:
186 delete a from #T a where ID not in (select max(ID) from #T where Name=a.Name)
187  
188 方法4(注:ID为唯一时可用):
189 delete a from #T a where ID not in(select max(ID)from #T group by Name)
190  
191 方法5:
192 delete a from #T a where (select count(1) from #T where Name=a.Name and ID>a.ID)>0
193  
194 方法6:
195 delete a from #T a where ID<>(select top 1 ID from #T where Name=a.name order by ID desc)
196  
197 方法7:
198 delete a from #T a where ID<any(select ID from #T where Name=a.Name)
199  
200  
201 select * from #T
202 /*
203 ID          Name Memo
204 ----------- ---- ----
205 3           A    A3
206 5           B    B2
207  
208 (2 行受影响)
209 */
210  
211  
212  
213  
214  
215 --3、删除重复记录没有大小关系时，处理重复值
216  
217  
218 --> --> (Roy)生成測試數據
219   
220 if not object_id('Tempdb..#T') is null
221     drop table #T
222 Go
223 Create table #T([Num] int,[Name] nvarchar(1))
224 Insert #T
225 select 1,N'A' union all
226 select 1,N'A' union all
227 select 1,N'A' union all
228 select 2,N'B' union all
229 select 2,N'B'
230 Go
231  
232 方法1:
233 if object_id('Tempdb..#') is not null
234     drop table #
235 Select distinct * into # from #T--排除重复记录结果集生成临时表#
236  
237 truncate table #T--清空表
238  
239 insert #T select * from #    --把临时表#插入到表#T中
240  
241 --查看结果
242 select * from #T
243  
244 /*
245 Num         Name
246 ----------- ----
247 1           A
248 2           B
249  
250 (2 行受影响)
251 */
252  
253 --重新执行测试数据后用方法2
254 方法2:
255  
256 alter table #T add ID int identity--新增标识列
257 go
258 delete a from  #T a where  exists(select 1 from #T where Num=a.Num and Name=a.Name and ID>a.ID)--只保留一条记录
259 go
260 alter table #T drop column ID--删除标识列
261  
262 --查看结果
263 select * from #T
264  
265 /*
266 Num         Name
267 ----------- ----
268 1           A
269 2           B
270  
271 (2 行受影响)
272  
273 */
274  
275 --重新执行测试数据后用方法3
276 方法3:
277 declare Roy_Cursor cursor local for
278 select count(1)-1,Num,Name from #T group by Num,Name having count(1)>1
279 declare @con int,@Num int,@Name nvarchar(1)
280 open Roy_Cursor
281 fetch next from Roy_Cursor into @con,@Num,@Name
282 while @@Fetch_status=0
283 begin 
284     set rowcount @con;
285     delete #T where Num=@Num and Name=@Name
286     set rowcount 0;
287     fetch next from Roy_Cursor into @con,@Num,@Name
288 end
289 close Roy_Cursor
290 deallocate Roy_Cursor
291  
292 --查看结果
293 select * from #T
294 /*
295 Num         Name
296 ----------- ----
297 1           A
298 2           B
299  
300 (2 行受影响)
301 */

删除重复数据保留最大id或最小id的SQL语句

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sqlserver 删除重复数据 保留最大id的SQL语句

SqlServer 删除重复数据 保留最大id的SQL语句

免责声明！

sqlserver 删除重复数据保留最大id的SQL语句

SqlServer 删除重复数据保留最大id的SQL语句