An SPQuery for lookup columns should be easy. Start the famous U2U Caml Editor, configure your query, and query the list.

This query will get a result if the lookup column stores something like “1;#1”. But if its value is e.g. “1;#Title”, the query will not return an item.

So what can we do about it?

Add a LookupId='TRUE' to your query, so it will look like this:

   1:  <Where>

   2:     <Eq>

   3:        <FieldRef Name='LookupField' LookupId='TRUE'/>

   4:        <Value Type='Lookup'>2</Value>

   5:     </Eq>

   6:  </Where>

Remember to omit the Query tags from the U2U Caml Editor when pasting the query into your Visual Studio source code!