Table: diving_world_series_venues
Columns: year
1st_venue
2nd_venue
3rd_venue
4th_venue
5th_venue

Question: How many 5th venue cities were there when Doha was the 1st venue city?
SQL: SELECT COUNT("5th_venue") FROM diving_world_series_venues WHERE "1st_venue" = 'Doha'

Question: When Qingdao was the 1st venue city, how many 2nd venue cities were there? 
SQL: SELECT COUNT("2nd_venue") FROM diving_world_series_venues WHERE "1st_venue" = 'Qingdao'

Question: In 2010, how many 1st venue cities were there? 
SQL: SELECT COUNT("1st_venue") FROM diving_world_series_venues WHERE "year" = 2010

Question: When Qingdao was the 1st venue city, who was in the 2nd venue?
SQL: SELECT "2nd_venue" FROM diving_world_series_venues WHERE "1st_venue" = 'Qingdao'

Question: What city was in the 3rd venue when Mexico City was in the 2nd? 
SQL: SELECT "3rd_venue" FROM diving_world_series_venues WHERE "2nd_venue" = 'Mexico City'