CREATE TABLE "dvd_releases" (
  "season" text,
  "date_released" text,
  "num_of_episodes" real,
  "num_of_discs" real,
  "special_features" text
);

Question: On how many dates was the complete 4th series released?
SQL: SELECT COUNT("date_released") FROM "dvd_releases" WHERE "season"='The Complete 4th Series';

Question: How many discs for the complete 4th series?
SQL: SELECT MAX("num_of_discs") FROM "dvd_releases" WHERE "season"='The Complete 4th Series';

Question: What day was the complete 2nd series: volume one released?
SQL: SELECT "date_released" FROM "dvd_releases" WHERE "season"='The Complete 2nd Series: Volume One';