CREATE TABLE people (People_ID INT, District TEXT, Name TEXT, Party TEXT, Age INT)
CREATE TABLE debate (Debate_ID INT, Date TEXT, Venue TEXT, Num_of_Audience INT)
CREATE TABLE debate_people (Debate_ID INT, Affirmative INT, Negative INT, If_Affirmative_Win BOOLEAN)

A bar chart showing the number of debates in each venue for those on the affirmative side, and show bar in descending order please.
SELECT Venue, COUNT(Venue) FROM debate_people AS T1 JOIN debate AS T2 ON T1.Debate_ID = T2.Debate_ID JOIN people AS T3 ON T1.Affirmative = T3.People_ID GROUP BY Venue ORDER BY Venue DESC
SELECT "Venue", COUNT("Venue") FROM "debate_people" AS "T1" JOIN "debate" AS "T2" ON "T1"."Debate_ID" = "T2"."Debate_ID" JOIN "people" AS "T3" ON "T1"."Affirmative" = "T3"."People_ID" GROUP BY "Venue" ORDER BY "Venue" DESC NULLS LAST