Which player has the highest salary on the list?
select player_id from salary order by salary desc limit 1
How many players has the birth country in USA?
select count ( player_id ) from player where birth_country = 'USA'
State the team id which has the highest rank in the list?
select team_id from team order by rank limit 1
List player's first name and last name who received salary from team Washington Nationals in both 2005 and 2007?
select t2.name_first, t2.name_last from salary as t1 join player as t2 on t1.player_id = t2.player_id join team as t3 on t3.team_id_br = t1.team_id where t1.year = 2005 and t3.name = 'Washington Nationals' intersect select t2.name_first, t2.name_last from salary as t1 join player as t2 on t1.player_id = t2.player_id join team as t3 on t3.team_id_br = t1.team_id where t1.year = 2007 and t3.name = 'Washington Nationals'