Mysql works, but find_by_sql returns different result!

I have a very strange issue when trying to use find_by_sql with Rails
3.0.7. Rails doesn’t return anything (empty result, []) but if I copy &
paste that exact same query into mysql, it returns a result.

This is what I’m trying in Rails:

Document.find_by_sql([“select d.* from documents d, categorizations cg,
combinations co where = cg.document_id and =
cg.combination_id and co.assigned_parent_category_id=?”, 1)

returns: []

and this is what I do in mysql: (the exact same query from above)

select documents.* from documents, categorizations, combinations where = categorizations.document_id and =
categorizations.combination_id and

returns: 1 result

Could this be a Rails bug or am I doing something wrong??

Thanks in advance!