Table: tv_series_dvd
Columns: complete_series
region_1
region_2
region_4
dvd_extras_and_bonus_features
number_of_discs

Question: What is the region 2 for the complete fifth series?
SQL: SELECT "region_2" FROM tv_series_dvd WHERE "complete_series" = 'The Complete Fifth Series'

Question: What is the number of region 4 for the series of the complete seventh series?
SQL: SELECT COUNT("region_4") FROM tv_series_dvd WHERE "complete_series" = 'The Complete Seventh Series'

Question: What is the region 1 where region 4 is tba is the complete eighth series?
SQL: SELECT "region_1" FROM tv_series_dvd WHERE "region_4" = 'TBA' AND "complete_series" = 'The Complete Eighth Series'

Question: Name the region 4 for the complete fifth series
SQL: SELECT "region_4" FROM tv_series_dvd WHERE "complete_series" = 'The Complete Fifth Series'