How many locations have the callsign DXGH?
CREATE TABLE "dzrh_nationwide" (
  "branding" text,
  "callsign" text,
  "frequency" text,
  "power_k_w" text,
  "station_type" text,
  "location" text
);
SELECT COUNT("location") FROM "dzrh_nationwide" WHERE "callsign"='DXGH';