Question

I’m migrating my MySQL databases to PostgreSQL. While connecting database to my Python script I’m getting some syntax error. So could you please convert this MySQL query into PostgreSQL:

select ifnull((select ifnull(run_id,0) from searchbank order by run_id desc limit 0,1),0)

Answer 1

Postgres doesn’t support ifnull:

select coalesce((select coalesce(run_id,0)
                 from searchbank
                 order by run_id desc limit 0,1),0
               )

You might find this version slightly cleaner and clearer:

select coalesce(max(run_id), 0)
from searchbank