The question is what aspect of the queries are you trying to test?
If you are trying to test that the queries are formed as you would expect you can compare the query to the expected string with expect_equal().
If you are trying to test that the query returns the results you expect you would either need to run the query against the database directly, stand up a local database with test data using something like SQLite, or use mock tests for the queries.
Also if you are using glue with SQL be sure to use glue_sql()!