Question: Find the average ranking for each player and their first name.
Schema: create table players (first_name varchar, player_id varchar, PRIMARY KEY (first_name)); create table rankings (player_id varchar, PRIMARY KEY (player_id))
SQL: select avg(ranking), t1.first_name from players as t1 join rankings as t2 on t1.player_id = t2.player_id group by t1.first_name