I put together a sample scenario of my issue and I hope its enough for someone to point me in the right direction.
I have two tables
Products
Product Meta
I need a result set of the following
I realize this is two years old, but it bugs me that the accepted answer calls for using dynamic SQL and the most upvoted answer won't work:
Select P.ProductId, P.Name
, Min( Case When PM.MetaKey = 'A' Then PM.MetaValue End ) As A
, Min( Case When PM.MetaKey = 'B' Then PM.MetaValue End ) As B
, Min( Case When PM.MetaKey = 'C' Then PM.MetaValue End ) As C
From Products As P
Join ProductMeta As PM
On PM.ProductId = P.ProductId
Group By P.ProductId, P.Name
You must use a Group By or you will get a staggered result. If you are using a Group By, you must wrap each column that is not in the Group By clause in an aggregate function (or a subquery).
We've successfully used the following approach in the past...
SELECT [p].ProductID,
[p].Name,
MAX(CASE [m].MetaKey
WHEN 'A'
THEN [m].MetaValue
END) AS A,
MAX(CASE [m].MetaKey
WHEN 'B'
THEN [m].MetaValue
END) AS B,
MAX(CASE [m].MetaKey
WHEN 'C'
THEN [m].MetaValue
END) AS C
FROM Products [p]
INNER JOIN ProductMeta [m]
ON [p].ProductId = [m].ProductId
GROUP BY [p].ProductID,
[p].Name
It can also be useful transposing aggregations with the use of...
SUM(CASE x WHEN 'y' THEN yVal ELSE 0 END) AS SUMYVal
EDIT
Also worth noting this is using ANSI standard SQL and so it will work across platforms :)
If your database engine is 2005 and your database is in 2000 compatibility mode, you can work around the lower compatibility mode by running your query from a 2005 database. Target the 2000 database by using 3 part naming convention for your tables in the query such as DatabaseNameHere.dbo.TableNameHere
Select a.ProductId
,a.Name
,(Select c.MetaValue
From [Product Meta] c
Where c.ProductId = a.ProductId
And c.MetaKey = 'A') As 'A'
,(Select d.MetaValue
From [Product Meta] d
Where d.ProductId = a.ProductId
And d.MetaKey = 'B') As 'B'
,(Select e.MetaValue
From [Product Meta] e
Where e.ProductId = a.ProductId
And e.MetaKey = 'C') As 'C'
From Products a
Order By a.ProductId Asc
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