Table: player_stats_20
Columns: nationality
no_a
pos_a
from
school_club
pts_b
reb_b
ast_b

Question: What is the points that is more than 636 and has a value of 50?
SQL: SELECT "pts_b" FROM player_stats_20 WHERE "reb_b" > 636 AND "no_a" = '50'

Question: Which rebound was 8 and has and ast that was less than 57?
SQL: SELECT AVG("reb_b") FROM player_stats_20 WHERE "no_a" = '8' AND "ast_b" < 57