How many players with first name Len and last name Barker are there?
select count(*) from player where name_first = 'Len' and name_last = 'Barker'
What is the average salary that he won in his career?
select avg(t1.salary) from salary as t1 join player as t2 on t1.player_id = t2.player_id where t2.name_first = 'Len' and t2.name_last = 'Barker'
What is the total salary that he won in his career?
select sum(t1.salary) from salary as t1 join player as t2 on t1.player_id = t2.player_id where t2.name_first = 'Len' and t2.name_last = 'Barker'
How about the total salary between 1985 to 1990?
select sum(t1.salary) from salary as t1 join player as t2 on t1.player_id = t2.player_id where t2.name_first = 'Len' and t2.name_last = 'Barker' and t1.year between 1985 and 1990;