CREATE TABLE "table1_28019988_5" (
  "series_num" real,
  "season_num" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text,
  "production_code" text,
  "u_s_viewers_million" text
);

Question: What episode number of the series had a production code of bdf409?
SQL: SELECT MIN("series_num") FROM "table1_28019988_5" WHERE "production_code"='BDF409';

Question: What episode number of the season was written by Tom Garrigus and had 2.31 million u.s. viewers?
SQL: SELECT MAX("season_num") FROM "table1_28019988_5" WHERE "u_s_viewers_million"='2.31' AND "written_by"='Tom Garrigus';

Question: What is the highest numbered episode in the series?
SQL: SELECT MAX("series_num") FROM "table1_28019988_5";

Question: What episode number in the series had a production code of bdf405?
SQL: SELECT MIN("series_num") FROM "table1_28019988_5" WHERE "production_code"='BDF405';