title: Find difference between two big tables in PostgreSQL
body: <p>I have two similar tables in Postgres with just one 32-byte latin field (simple md5 hash).
  Both tables have ~30,000,000 rows. Tables have little difference (10-1000 rows are different)</p>
  
  <p>Is it possible with Postgres to find a difference between these tables, the result should be  10-1000 rows I described above.</p>
  
  <p>This is not a real task, I just want to know about how PostgreSQL deals with JOIN-like logic.</p>