各位高手请教，用SQL语句进行分组统计的问题
向各位高手请教下，如何才能用SQL语句实现统计工序的最后一条及并显示出来，谢谢啦！
表InfoTable
序号工序信息时间
111.22012-8-1
211.42012-8-2
311.82012-8-3
411.62012-8-4
521.22012-8-5
621.42012-8-6
722.12012-8-7
832.32012-8-8
932.82012-8-9
1031.22012-8-10
1131.42012-8-11
1232.12012-8-12
1332.32012-8-13
查询结果为：
序号工序信息时间
411.62012-8-4
722.12012-8-7
1332.32012-8-13
谢谢啦！
[解决办法]
if object_id('[InfoTable]') is not null drop table [InfoTable]create table [InfoTable]([序号] int,[工序] int,[信息] varchar(10),[时间] datetime)goinsert into [InfoTable]select 1, 1, '1.2', '2012-8-1' union allselect 2, 1, '1.4', '2012-8-2' union allselect 3, 1, '1.8', '2012-8-3' union allselect 4, 1, '1.6', '2012-8-4' union allselect 5, 2, '1.2', '2012-8-5' union allselect 6, 2, '1.4', '2012-8-6' union allselect 7, 2, '2.1', '2012-8-7' union allselect 8, 3, '2.3', '2012-8-8' union allselect 9, 3, '2.8', '2012-8-9' union allselect 10, 3, '1.2', '2012-8-10' union allselect 11, 3, '1.4', '2012-8-11' union allselect 12, 3, '2.1', '2012-8-12' union allselect 13, 3, '2.3', '2012-8-13' select [序号],[工序],[信息], [时间] from [InfoTable]where [序号] in (select max(t.[序号]) '序号' from [InfoTable] t group by t.[工序])/*(13 行受影响)序号 工序 信息 时间----------- ----------- ---------- -----------------------4 1 1.6 2012-08-04 00:00:00.0007 2 2.1 2012-08-07 00:00:00.00013 3 2.3 2012-08-13 00:00:00.000(3 行受影响)*/
[解决办法]
--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 #TGoCreate table #T([ID] int,[Name] nvarchar(1),[Memo] nvarchar(2))Insert #Tselect 1,N'A',N'A1' union allselect 2,N'A',N'A2' union allselect 3,N'A',N'A3' union allselect 4,N'B',N'B1' union allselect 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 A14 B B1(2 行受影响)*/--II、Name相同ID最大的记录,与min相反: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 max(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID order by ID方法3:select * from #T a where ID=(select max(ID) from #T where Name=a.Name) order by ID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 max(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 desc)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 max(ID) from #T group by Name)--SQL2005:方法10:select ID,Name,Memo from (select *,max(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 desc) as MinID from #T a)T where MinID=1生成结果2:/*ID Name Memo----------- ---- ----3 A A35 B B2(2 行受影响)*/--2、删除重复记录有大小关系时,保留大或小其中一个记录--> --> (Roy)生成測試數據if not object_id('Tempdb..#T') is null drop table #TGoCreate table #T([ID] int,[Name] nvarchar(1),[Memo] nvarchar(2))Insert #Tselect 1,N'A',N'A1' union allselect 2,N'A',N'A2' union allselect 3,N'A',N'A3' union allselect 4,N'B',N'B1' union allselect 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 A14 B B1(2 行受影响)*/--II、Name相同ID保留最大的一条记录: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 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方法3:delete a from #T a where ID not in (select max(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 max(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 desc)方法7:delete a from #T a where ID<any(select ID from #T where Name=a.Name)select * from #T/*ID Name Memo----------- ---- ----3 A A35 B B2(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 #TGoCreate table #T([Num] int,[Name] nvarchar(1))Insert #Tselect 1,N'A' union allselect 1,N'A' union allselect 1,N'A' union allselect 2,N'B' union allselect 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 A2 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godelete 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goalter table #T drop column ID--删除标识列--查看结果select * from #T/*Num Name----------- ----1 A2 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 forselect count(1)-1,Num,Name from #T group by Num,Name having count(1)>1declare @con int,@Num int,@Name nvarchar(1)open Roy_Cursorfetch next from Roy_Cursor into @con,@Num,@Namewhile @@Fetch_status=0begin set rowcount @con; delete #T where Num=@Num and Name=@Name set rowcount 0; fetch next from Roy_Cursor into @con,@Num,@Nameendclose Roy_Cursordeallocate Roy_Cursor--查看结果select * from #T/*Num Name----------- ----1 A2 B(2 行受影响)*/
[解决办法]
IF OBJECT_ID('T') IS NOT NULL DROP TABLE TGOCREATE TABLE T(序号 INT ,样本编号 INT,工序 INT ,信息 DECIMAL(18,2),时间 DATETIME)GOINSERT INTO TSELECT 1,1,1,1.2,'2012-8-1' UNION ALLSELECT 2,2,1,1.4,'2012-8-2' UNION ALLSELECT 3,3,1,1.8,'2012-8-3' UNION ALLSELECT 4,1,1,1.6,'2012-8-4' UNION ALLSELECT 5,2,1,1.2,'2012-8-5' UNION ALLSELECT 6,3,1,1.4,'2012-8-6' UNION ALLSELECT 7,1,2,2.1,'2012-8-7' UNION ALLSELECT 8,2,2,2.3,'2012-8-8' UNION ALLSELECT 9,3,2,2.8,'2012-8-9' UNION ALLSELECT 10,1,2,1.2,'2012-8-10' UNION ALLSELECT 11,2,2,1.4,'2012-8-11' UNION ALLSELECT 12,3,2,2.1,'2012-8-12' UNION ALLSELECT 13,1,2,2.3,'2012-8-13' UNION ALLSELECT 14,2,2,1.6,'2012-8-14' UNION ALLSELECT 15,3,2,1.2,'2012-8-15' UNION ALLSELECT 16,1,3,1.4,'2012-8-16' UNION ALLSELECT 17,2,3,2.1,'2012-8-17' UNION ALLSELECT 18,3,3,2.3,'2012-8-18' UNION ALLSELECT 19,1,3,2.8,'2012-8-19' UNION ALLSELECT 20,2,3,1.2,'2012-8-20' UNION ALLSELECT 21,3,3,1.6,'2012-8-21' UNION ALLSELECT 22,1,3,1.2,'2012-8-22' UNION ALLSELECT 23,2,3,1.4,'2012-8-23' UNION ALLSELECT 24,3,3,2.1,'2012-8-24' GOSELECT * FROM (SELECT RIndex=ROW_NUMBER() OVER(PARTITION BY 样本编号,工序 ORDER BY 时间 desc),* FROM T) t WHERE RIndex=1 order by 序号