List the name and gender of players
select player_name, gender from player
How many coaches are there?
select count(*) from coach
Show the name of each player and also the corresponding coach name of each.
select t3.player_name, t2.coach_name from player_coach as t1 join coach as t2 on t1.coach_id = t2.coach_id join player as t3 on t1.player_id = t3.player_id