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Controlling JOIN Hierarchy in SQL2000 without CTE

Posted on 2008-06-23
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Last Modified: 2010-10-05
I am joining on a set of data in SQL2000, and would like to control the hierarchy of which JOIN is used when given a choice of matches.

I can assign a numeric value to the data set, so I only need to JOIN on the lowest/highest number available.

So for example on the below if joining on the middle column with B, I would want to return 250, not another value.

1     A    150
1     B     250
2     A     330
2     B     558
3     A     554
3     B     447
3     C     557
0
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Question by:rickchild
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6 Comments
 
LVL 17

Expert Comment

by:dbaSQL
ID: 21845402
possibly just use MIN or MAX in your select?
0
 
LVL 18

Assisted Solution

by:lludden
lludden earned 50 total points
ID: 21845562
SELECT P1 FROM T1 INNER JOIN (SELECT ColB, MIN(ColC) FROM Table2 GROUP BY ColB) T2 ON T1.ColB = T2.ColB
0
 
LVL 17

Accepted Solution

by:
dbaSQL earned 200 total points
ID: 21845573
i used TOP instead of MIN/MAX.  i'm not sure if this is what you're looking for:

create table test (one int, two char(1), three int)
insert test
select  1,'A',150
union
select 1,'B',250
union
select 2,'A',330
union
select 2,'B',558
union
select 3,'A',554
union
select 3,'B',447
union
select 3,'C',557

select * from test

select TOP 1 a.one,a.two,a.three from test a inner join test b
on a.one = b.one
where a.two = 'b'
group by a.one,a.two,a.three
0
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LVL 13

Author Comment

by:rickchild
ID: 21863459
lludden: I will try youtr solution now

dbaSQL: Your solutions is fairly similar to mine, but the problem I am having is that I am trying to use this query to join onto another table, and I seem unable to pass in the 'b' from the first table.

I either need to pass in the Code to the WHERE, or be able to work on the hierarchy when I join it to the main table


LEFT JOIN
(
    SELECT TOP 1 * FROM
    (
	SELECT * FROM
	(
		SELECT 1 as Orders, Entity, Code, Description from revenuereporting..tbl_DIMProduct
		WHERE Entity = 'ASL' and Code = L.[Product Name]
		UNION
		SELECT 2 as Orders, Entity, Code, Description from revenuereporting..tbl_DIMProduct
		WHERE Entity = 'Inc' and Code =  L.[Product Name]
	) AS FFFF
    ) as FF
) as F
ON L.[Product Name] = F.Code

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0
 
LVL 13

Author Comment

by:rickchild
ID: 21863551
PS.  This will work if I pass in the Code as a variable, but I am in SSRS so struggling to get that to work.
0
 
LVL 13

Author Comment

by:rickchild
ID: 21863912
Think I may have sussed this now using a subquery generated column, rather than joining on a subquery.

The hierarchy just depends on the order of the UNION, which is ok for this case.
select a.*, (
		select top 1 Description FROM
		(
		SELECT Code, Description
		FROM revenuereporting..tbl_DIMProduct
		WHERE Entity = 'ASL' and Code = a.Code
		UNION ALL 
		SELECT Code, Description
		FROM revenuereporting..tbl_DIMProduct
		WHERE Entity = b.Entity and Code = a.Code
		) as Description
	) as Description

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0

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