Table: grand_canyon_camping
Columns: area
name
zone
group_s
parties
max_people
camp_type

Question: What zone has camp type D/S in area Bl9?
SQL: SELECT "zone" FROM grand_canyon_camping WHERE "camp_type" = 'd/s' AND "area" = 'bl9'

Question: Which name has group 0 in Bl4 area?
SQL: SELECT "name" FROM grand_canyon_camping WHERE "group_s" = 0 AND "area" = 'bl4'

Question: Which zone has max capacity of 23 in a group under 2 at Robbers Roost?
SQL: SELECT "zone" FROM grand_canyon_camping WHERE "max_people" > 23 AND "group_s" < 2 AND "name" = 'robbers roost'