Which source has a Cost free, and an Activity of some, and an Editor of markitup?
CREATE TABLE "list_of_source_code_editors" (
  "editor" text,
  "site" text,
  "style_clone_of" text,
  "cost_us" text,
  "open_source" text,
  "activity" text
);
SELECT "open_source" FROM "list_of_source_code_editors" WHERE "cost_us"='free' AND "activity"='some' AND "editor"='markitup';