CREATE TABLE table_name_19 (area_of_operation VARCHAR, services VARCHAR, years_of_operation VARCHAR)

Where is the area of operation that had drilling during the year 1999?
SELECT area_of_operation FROM table_name_19 WHERE services = "drilling" AND years_of_operation = "1999"
SELECT "area_of_operation" FROM "table_name_19" WHERE "1999" = "years_of_operation" AND "drilling" = "services"