drop table sales; ERROR: cannot drop table sales because other objects depend on it DETAIL: constraint car_sales_id_fkey on table car depends on table sales HINT: Use DROP ... CASCADE to drop the dependent objects too.

Solution :
Becouse foreign key is there in sales table so if you want to delete that table you need to specify Cascade option

postgres=# drop table sales;
ERROR:  cannot drop table sales because other objects depend on it
DETAIL:  constraint car_sales_id_fkey on table car depends on table sales
HINT:  Use DROP ... CASCADE to drop the dependent objects too.

postgres=# drop table sales cascade;
NOTICE:  drop cascades to constraint car_sales_id_fkey on table car
DROP TABLE

Do you want to learn  More About foreign Key  Click The Below Link

FOREIGN KEY