Table: qb_400_yards
Columns: rank
rating
completion_percentage
touchdown_percentage
yards_per_attempt
total_yards

Question: What is the completion percentage when yards per attempt was done by Steve McNair : 2003?
SQL: SELECT "completion_percentage" FROM qb_400_yards WHERE "yards_per_attempt" = 'Steve McNair : 2003'

Question: What rank has a rating of 146.8? 
SQL: SELECT "rank" FROM qb_400_yards WHERE "rating" = '146.8'

Question: How many yards per attempt were there when total yards were 513?
SQL: SELECT "yards_per_attempt" FROM qb_400_yards WHERE "total_yards" = '513'