Table: giants_1986_season
Columns: week
date
opponent
result
game_site
attendance

Question: where was the game site when the opponent was san diego chargers?
SQL: SELECT "game_site" FROM giants_1986_season WHERE "opponent" = 'san diego chargers'

Question: who was the opponent when the week was 9?
SQL: SELECT "opponent" FROM giants_1986_season WHERE "week" = '9'