CREATE TABLE "escorts" (
  "name" text,
  "class" text,
  "navy" text,
  "date_joined" text,
  "date_departed" text
);

Question: What's the departed date for Grimsby Class Sloop?
SQL: SELECT "date_departed" FROM "escorts" WHERE "class"='grimsby class sloop';

Question: What's the departed date that the HMS Leith of the Royal Navy?
SQL: SELECT "date_departed" FROM "escorts" WHERE "navy"='royal navy' AND "name"='hms leith';

Question: What's the class of the HMS Fowey?
SQL: SELECT "class" FROM "escorts" WHERE "name"='hms fowey';

Question: What's the class of the HMS Heartsease?
SQL: SELECT "class" FROM "escorts" WHERE "name"='hms heartsease';