Best tool nowadays has to be to spin up a database and execute the queries against it. If you are on a database setup that spinning up an instance takes a long

Best tool nowadays has to be to spin up a database and execute the queries against it. If you are on a database setup that spinning up an instance takes a long time, consider docker. Be wary of too many techniques that are supposed to be making it easier to test, but also make it hard for you to leave a query pipeline. In particular, SQL should be very easy in the "with these as our base inputs, we expect these as our base outputs." Trying to test individual parts of the queries is almost certainly doomed to massive bloat of the system and will cause grief later.