SELECT count(*) FROM player WHERE birth_country = 'USA' AND bats  =  'R';
How many players born in USA are right-handed batters? That is, have the batter value 'R'.
SELECT count ( * ) FROM player WHERE birth_country = 'USA ' AND bats = 'R ' ;
select count ( * ) from player where birth_country = value and bats = value
How many players born in USA are right-handed batters ? That is , have the batter value 'R ' .