CREATE TABLE "radio_series" (
  "date" text,
  "episode" real,
  "performer_1" text,
  "performer_2" text,
  "performer_3" text,
  "performer_4" text
);

Question: What is the average episode number where jimmy mulville was the 4th performer?
SQL: SELECT AVG("episode") FROM "radio_series" WHERE "performer_4"='jimmy mulville';

Question: What is the total number of episodes where hugh laurie was the 3rd performer?
SQL: SELECT COUNT("episode") FROM "radio_series" WHERE "performer_3"='hugh laurie';

Question: What is the lowest episode number where john bird was the 4th performer?
SQL: SELECT MIN("episode") FROM "radio_series" WHERE "performer_4"='john bird';

Question: Who was the 3rd performer when Rory Bremner was the 4th performer?
SQL: SELECT "performer_3" FROM "radio_series" WHERE "performer_4"='rory bremner';