Table: heavy_tanker_vehicles
Columns: category
sub_category
cab_size
drive_wheels
capacity_litres

Question: Name the number of cab size for 4 medium tanker
SQL: SELECT COUNT("cab_size") FROM heavy_tanker_vehicles WHERE "category" = '4 Medium tanker'

Question: Name the category for cab size crew and super tanker
SQL: SELECT "category" FROM heavy_tanker_vehicles WHERE "cab_size" = 'Crew' AND "sub_category" = 'Super tanker'

Question: Name the capacity for single cab size 2 medium tanker
SQL: SELECT "capacity_litres" FROM heavy_tanker_vehicles WHERE "cab_size" = 'Single' AND "category" = '2 Medium tanker'