Comments on: SQL Server 2008 R2: Reporting Services – Look Up, Look Down, Look All Around (Part III)

By: Data Inspirations » SQL Server 2008 R2: Reporting Services – Look Up, Look Down, Look All Around (Part II)

Thu, 02 Feb 2012 01:12:39 +0000

[...] my next post, I’ll explain the last of the lookup functions, [...]

By: Stacia Misner

Stacia Misner — Mon, 26 Dec 2011 23:09:42 +0000

Hi Mike, You can think of lookups as working like a left outer join in T-SQL, so using a lookup to stack two MDX datasets together wouldn’t work. If it’s possible for you, I would recommend approaching the problem by using an OPENQUERY function as I describe in this post: http://blog.datainspirations.com/2010/11/30/creating-a-linked-server-for-analysis-services/. Then you can have two select statements to get the results for each MDX dataset and perform a union on the two result sets.

By: Mike

Mike — Sat, 17 Dec 2011 00:58:56 +0000

Very nice article! I was hoping this would provide a solution to my issue which similar but different. I am trying to stack two MDX datasets together, very similar to a sql Union. Can lookups be used for this purpose?

By: Russell

Russell — Wed, 26 Oct 2011 11:54:55 +0000

Hi Marko

Can you let me know how you did that please.
Im really stuck.

Thanks

By: Marko

Marko — Thu, 02 Jun 2011 17:56:56 +0000

Never mind. Figured it out by passing the lookupset values to a custom function to convert and summarize.

By: Marko

Marko — Thu, 02 Jun 2011 17:35:12 +0000

Anyway to Sum() the values returned? I am looking to combine current year and last year sales into one tablix that are currently in different datasets. Tried doing a:
=SUM(LookupSet(Fields!StateProvinceCode.Value,Fields!StateProvinceCode.Value, Fields!CustomerID.Value,”Dataset2″)). Didn’t work.

By: Stacia Misner

Stacia Misner — Fri, 27 May 2011 22:36:00 +0000

Hi Mohamed,

Well, the example in the post shows how to get a count of the elements:

=LookupSet(Fields!StateProvinceCode.Value,Fields!StateProvinceCode.Value, Fields!CustomerID.Value,”Dataset2″).Length

And since the results is an array, we know that the count of elements less 1 is the index to the last element in the array. So to get the last element, you would use this expression.

=LookupSet(Fields!StateProvinceCode.Value,Fields!StateProvinceCode.Value, Fields!CustomerID.Value,”Dataset2″)(LookupSet(Fields!StateProvinceCode.Value,Fields!StateProvinceCode.Value, Fields!CustomerID.Value,”Dataset2″).Length -1)

I hope that helps! — Stacia

By: Mohamed

Mohamed — Mon, 16 May 2011 04:34:41 +0000

Hi, The LookupSet returns number of elements. I want take the Last element of that. How to do that?
Please help me.

Thanks..

By: Stacia Misner

Stacia Misner — Mon, 15 Nov 2010 21:40:01 +0000

The lookup functions don’t really perform a join in a T-SQL sense. All the work is performed on datasets after the query is performed. The behavior is more like a left join though because the results for dataset1 will display, although you might get an error if dataset2 doesn’t have a match for the lookup. You can add some error-trapping to your expression to deal with that. Handling a full join might be possible with some creative implementation of lookup functions using a combination of expressions, but it’s not handled natively by the lookup functions.

By: hDt

hDt — Thu, 11 Nov 2010 03:21:09 +0000

hi,

are these Lookup / MultiLookup / LookupSet functions performing a left join?

i need to do the following.

dataset1 returns 3 columns.
dataset2 returns 3 columns.

2 of the 3 columns on each are ‘primary keys’ to be matched, joined on.

i need to do a Full Join though, as i have values missing and/or present in both, so i want a full view across both datasets…

which option to use? is this possible..?

thanks !!