Table: grand_prix_results
Columns: round
date
grand_prix
circuit
motogp_winner
moto2_winner
125cc_winner
report

Question: How many MotoGP winners were there when the circuit was Catalunya?
SQL: SELECT COUNT("motogp_winner") FROM grand_prix_results WHERE "circuit" = 'Catalunya'

Question: Who are all the Moto2 winners when the grand prix was Shell Advance Malaysian Grand Prix?
SQL: SELECT "moto2_winner" FROM grand_prix_results WHERE "grand_prix" = 'Shell Advance Malaysian Grand Prix'

Question: Who are all the motogp winners when the circuit was Catalunya?
SQL: SELECT "motogp_winner" FROM grand_prix_results WHERE "circuit" = 'Catalunya'