每個訂單選擇1行，但包含order_line表？

Question

我有兩個表

order [ order_id ] 
order_line [ order_id, product_id, cat_id ] 

我要選擇每一個訂單&相關ORDER_LINE， 但我想每個訂單行，我只想從ORDER_LINE

選擇CAT_ID所以我要像一個結果這..

results: 
[0] order_id, cat_id1 , cat_id2, cat_id3 
[1] order_id, cat_id 

可能嗎？

Answer 1

這是基於回答my own question

CREATE FUNCTION [dbo].[GetCateogriesForOrder] 
(
    @orderID int 
) 
RETURNS varchar(max) 
AS 
BEGIN 
    declare @output varchar(max) 
    select @output = COALESCE(@output + ', ', '') + cat_id 
    from order_line 
    where order_id = @orderID 

    return @output 
END 

GO 

SELECT order_ID, dbo. GetCateogriesForOrder(order_ID) 
FROM order 

GO 

Answer 2

嘗試這個例子：

if object_id('tempdb..#student') is not null drop table #student 
create table #student 
(
sid int 
,sname varchar(10) 
,lastname varchar(10) 
,age int 
) 
insert #student select 1,'Joe','Block',20 
union all select 2,'Adam','Brad',30 
union all select 3,'Kevin','Campbell',33 
union all select 4,'Mike','Gust',40 
SELECT * FROM #student 
if object_id('tempdb..#course') is not null drop table #course 
create table #course 
(
cid int 
,sid int 
,coursename varchar(15) 
,duration int 
,courselanguage varchar(10), 
pos varchar(15) 
) 
insert #course select 1,1,'Maths',2,'English',2 
union all select 2,1,'Science4',1,'Spanish4',1 
union all select 2,1,'Science',1,'Spanish',3 
union all select 3,1,'Geography',1,'Dutch',4 
union all select 4,2,'Maths',2,'Dutch',2 
union all select 5,2,'Science',2,'English',4 
union all select 5,4,'test',545,'testlang',2 
SELECT * FROM #course 

declare @maxcourses int 
select @maxcourses=(select max(numcourses) 
from (select numcourses=count(*) 
from #course 
group by sid) q) 

declare @pivotlist varchar(max) 
,@pivotselectlist varchar(max) 
select @pivotlist= 
coalesce(@pivotlist+',','') 
+'Sub'+ix+',' 
+'Dur'+ix+',' 
+'Lang'+ix 
,@pivotselectlist= 
coalesce(@pivotselectlist+',','') 
+'Sub'+ix+'=coalesce(Sub'+ix+','''')'+',' 
+'Dur'+ix+'=coalesce(cast(Dur'+ix+' as int),0)'+',' 
+'Lang'+ix+'=coalesce(Lang'+ix+','''')' 
from (select ix=convert(varchar(3),Number) 
from master..spt_values 
where Type='P' and Number between 1 and @maxcourses) q 

declare @sql nvarchar(max) 
set @sql=' 
;with Rnums as 
(
select sid 
,coursename 
,duration 
,courselanguage 
,ix=pos 
from #course 
) 
,PivotInput as 
(
select sid 
,AttribName=case ColNo 
when 1 then ''Sub''+ix 
when 2 then ''Dur''+ix 
when 3 then ''Lang''+ix 
end 
,AttribVal=case ColNo 
when 1 then coursename 
when 2 then cast(duration as varchar(10)) 
when 3 then courselanguage 
end 
from Rnums 
cross join (select 1 union all 
select 2 union all 
select 3) Cols(ColNo) 
) 
,PivotCourses as 
(
select sid,'+@pivotlist+' 
from PivotInput 
pivot (max(AttribVal) for AttribName 
in ('+@pivotlist+') 
) PivotOutput 
) 
select s.sid 
,sname 
,lastname 
,age 
,'+@pivotselectlist+' 
from #student s 
join PivotCourses c on s.sid=c.sid' 

--print @sql 
exec sp_executesql @sql 

Answer 3

嘗試此

declare @maxOrderCat int 
select @maxOrderCat=(select max(numOrderCat) 
from (select numOrderCat=count(*) 
from order_line 
group by order_id) q) 

declare @pivotlist varchar(max) 
,@pivotselectlist varchar(max) 
select @pivotlist= 
coalesce(@pivotlist+',','') 
+'cat_id'+ix 
,@pivotselectlist= 
coalesce(@pivotselectlist+',','') 
+'cat_id'+ix+'=coalesce(cat_id'+ix+','''')' 
from (select ix=convert(varchar(3),Number) 
from master..spt_values 
where Type='P' and Number between 1 and @maxOrderCat) q 
--Select @pivotselectlist 
declare @sql nvarchar(max) 
set @sql=' 
;with Rnums as 
(
select order_id 
,cat_id 
,ix=convert(varchar,position) 
from order_line 
) 
,PivotInput as 
(
select order_id 
,AttribName=case ColNo 
when 1 then ''cat_id''+ix 
end 
,AttribVal=case ColNo 
when 1 then cat_id 
end 
from Rnums 
cross join (select 1 
) Cols(ColNo) 
) 
,PivotOrderCat as 
(
select order_id,'+@pivotlist+' 
from PivotInput 
pivot (max(AttribVal) for AttribName 
in ('+@pivotlist+') 
) PivotOutput 
) 
select s.order_id 
,'+@pivotselectlist+' 
from Orders s 
join PivotOrderCat c on s.order_id=c.order_id' 

exec sp_executesql @sql