Question

I have a table profiles containing people with a primary key login_hash and a bunch of other fields (for example, age). Another table, msgs, contains src and dest fields, both of which are foreign keys to login_hash from the profiles table. How do I retrieve the ages of the src and dests in one sqlite3 (from Python) query?

Answer 1

You can use two inner joins:

SELECT m.*, p1.*, p2.*
  FROM msgs m
INNER JOIN profiles p1 ON m.src = p1.login_hash
INNER JOIN profiles p2 ON m.dest = p2.login_hash