Which song by David Essex spent 2 weeks on top of the charts?
CREATE TABLE "see_also" (
  "volume_issue" text,
  "issue_date_s" text,
  "weeks_on_top" real,
  "song" text,
  "artist" text
);
SELECT "song" FROM "see_also" WHERE "weeks_on_top"=2 AND "artist"='david essex';