Question

I have a table that looks like this:

Month      Site          Val
2009-12    Microsoft      10
2009-11    Microsoft      12
2009-10    Microsoft      13
2009-12    Google         20
2009-11    Google         21
2009-10    Google         22

And I want to get a 2-dimension table that gives me the “Val” for each site’s month, like:

Month      Microsoft      Google
2009-12        10           20
2009-11        12           21
2009-10        13           22

But the catch is, I don’t know all the possible values that can be in “Site”. If a new site appears, I want to automatically get a new column in my resulting table.

All the code samples I saw that could do this required me to hardcode “Microsoft and Google” in the query text.
I saw one that didn’t, but it was basically faking it by listing the Sites and generating a query on the fly (concatting a string) that had those column names in it.

Isn’t there a way to get SQL Server 2008 to do this without a hack like that?

NOTE: I need to be able to run this as a query that I send from ASP.Net, I can’t do stored procedures or other stuff like that.

Thanks!
Daniel

Answer 1

The example you linked to uses dynamic SQL. Unfortunately, there is no other built-in method for pivoting in SQL Server when the output columns are not known in advance.

If the data is not too large, it’s probably easiest to simply run a normal row query from ASP.NET and perform your pivot in the application code. If the data is very large, then you’ll have to generate the SQL dynamically after first querying for the possible column values.

Note that you don’t actually need to write a SQL statement that generates dynamic SQL; you can simply generating the SQL in ASP.NET, and that will most likely be much easier. Just don’t forget to escape the distinct Site values before chucking them in a generated query, and don’t forget to parameterize whatever parts of the SQL statement that you normally would without the pivot.