if not object_id('Tab') is null drop table Tab Go Create table Tab([Col1] int,[Col2] nvarchar(1)) Insert Tab select 1,N'a' union all select 1,N'b' union all select 1,N'c' union all select 2,N'd' union all select 2,N'e' union all select 3,N'f' Go合并表:SQL2000用函数:go if object_id('F_Str') is not null drop function F_Str go create function F_Str(@Col1 int) returns nvarchar(100) as begin declare @S nvarchar(100) select @S=isnull(@S+',','')+Col2 from Tab where Col1=@Col1 return @S end go Select distinct Col1,Col2=dbo.F_Str(Col1) from TabgoSQL2005用XML:方法1:select a.Col1,Col2=stuff(b.Col2.value('/R[1]','nvarchar(max)'),1,1,'') from (select distinct COl1 from Tab) a Cross apply (select COl2=(select N','+Col2 from Tab where Col1=a.COl1 For XML PATH(''), ROOT('R'), TYPE))b方法2:select a.Col1,COl2=replace(b.Col2.value('/Tab[1]','nvarchar(max)'),char(44)+char(32),char(44)) from (select distinct COl1 from Tab) a cross apply (select Col2=(select COl2 from Tab where COl1=a.COl1 FOR XML AUTO, TYPE) .query('<Tab> {for $i in /Tab[position()<last()]/@COl2 return concat(string($i),",")} {concat("",string(/Tab[last()]/@COl2))} </Tab>') )bSQL05用CTE:;with roy as(select Col1,Col2,row=row_number()over(partition by COl1 order by COl1) from Tab) ,Roy2 as (select COl1,cast(COl2 as nvarchar(100))COl2,row from Roy where row=1 union all select a.Col1,cast(b.COl2+','+a.COl2 as nvarchar(100)),a.row from Roy a join Roy2 b on a.COl1=b.COl1 and a.row=b.row+1) select Col1,Col2 from Roy2 a where row=(select max(row) from roy where Col1=a.COl1) order by Col1 option (MAXRECURSION 0) 生成结果: /* Col1 COl2 ----------- ------------ 1 a,b,c 2 d,e 3 f(3 行受影响) */
--猜猜看 select distinct * from tb where 夹具id in (13,16) and 检具id in (14,17) and 模具id=15
你指的重复数据是什么呢? 以什么为标准,即哪些列重复就要去掉,去掉的那些行,以哪个列为标准来保留? 哪些列重复不算?select * from tb a where not exists(select 1 from tb where 不允许重复的列名=a.不允许重复的列名 and 判定为重复的行中不重复的列>a.判定为重复的行中不重复的列 --示例: select * from tb a where not exists(select 1 from tb where 模具夹具名称=a.模具夹具名称 and 模具夹具加工日期>a.模具夹具加工日期
if not object_id('Tab') is null
drop table Tab
Go
Create table Tab([Col1] int,[Col2] nvarchar(1))
Insert Tab
select 1,N'a' union all
select 1,N'b' union all
select 1,N'c' union all
select 2,N'd' union all
select 2,N'e' union all
select 3,N'f'
Go合并表:SQL2000用函数:go
if object_id('F_Str') is not null
drop function F_Str
go
create function F_Str(@Col1 int)
returns nvarchar(100)
as
begin
declare @S nvarchar(100)
select @S=isnull(@S+',','')+Col2 from Tab where Col1=@Col1
return @S
end
go
Select distinct Col1,Col2=dbo.F_Str(Col1) from TabgoSQL2005用XML:方法1:select
a.Col1,Col2=stuff(b.Col2.value('/R[1]','nvarchar(max)'),1,1,'')
from
(select distinct COl1 from Tab) a
Cross apply
(select COl2=(select N','+Col2 from Tab where Col1=a.COl1 For XML PATH(''), ROOT('R'), TYPE))b方法2:select
a.Col1,COl2=replace(b.Col2.value('/Tab[1]','nvarchar(max)'),char(44)+char(32),char(44))
from
(select distinct COl1 from Tab) a
cross apply
(select Col2=(select COl2 from Tab where COl1=a.COl1 FOR XML AUTO, TYPE)
.query('<Tab>
{for $i in /Tab[position()<last()]/@COl2 return concat(string($i),",")}
{concat("",string(/Tab[last()]/@COl2))}
</Tab>')
)bSQL05用CTE:;with roy as(select Col1,Col2,row=row_number()over(partition by COl1 order by COl1) from Tab)
,Roy2 as
(select COl1,cast(COl2 as nvarchar(100))COl2,row from Roy where row=1
union all
select a.Col1,cast(b.COl2+','+a.COl2 as nvarchar(100)),a.row from Roy a join Roy2 b on a.COl1=b.COl1 and a.row=b.row+1)
select Col1,Col2 from Roy2 a where row=(select max(row) from roy where Col1=a.COl1) order by Col1 option (MAXRECURSION 0)
生成结果:
/*
Col1 COl2
----------- ------------
1 a,b,c
2 d,e
3 f(3 行受影响)
*/
select distinct * from tb where 夹具id in (13,16) and 检具id in (14,17) and 模具id=15
以什么为标准,即哪些列重复就要去掉,去掉的那些行,以哪个列为标准来保留?
哪些列重复不算?select * from tb a where not exists(select 1 from tb where 不允许重复的列名=a.不允许重复的列名 and 判定为重复的行中不重复的列>a.判定为重复的行中不重复的列
--示例:
select * from tb a where not exists(select 1 from tb where 模具夹具名称=a.模具夹具名称 and 模具夹具加工日期>a.模具夹具加工日期
嗯,谢谢你的回答,我想要的效果是这样的,图在9楼,夹具id 夹具项目名称 检具id 检具项目名称 模具id 模具项目名称 13 夹具精细加工 14 检具初步加工 15 模具初步加工
16 夹具精加工 17 检具二次加工就像这样来显示,没有 重复的数据。 这个可以实现出来吗?