CREATE TABLE table_name_94 (gross_tonnage NUMBER, ship VARCHAR2, date_commissioned VARCHAR2)

Tell me the sum of Gross Tonnage for isis ship on date commisioned less than 1842
SELECT SUM(gross_tonnage) FROM table_name_94 WHERE ship = "isis" AND date_commissioned < 1842
SELECT SUM("gross_tonnage") FROM "table_name_94" WHERE "date_commissioned" < 1842 AND "isis" = "ship"