CREATE TABLE "vessels" (
  "vessel" text,
  "origin" text,
  "type" text,
  "in_service" real,
  "unit" text
);

Question: What type of ship is a Kobben class vessel that has been in service longer than 2?
SQL: SELECT "type" FROM "vessels" WHERE "in_service">2 AND "vessel"='kobben class';

Question: What is the unit for a submarine type ship from Norway?
SQL: SELECT "unit" FROM "vessels" WHERE "type"='submarine' AND "origin"='norway';