Table: dvd_volume
Columns: dvd_name
ep_no
dvd_no
release_date
additional_information

Question: What is the largest number of DVDs?
SQL: SELECT MAX("dvd_no") FROM dvd_volume

Question: What is the highest number of episodes?
SQL: SELECT MAX("ep_no") FROM dvd_volume

Question: What is the most recent release date?
SQL: SELECT MAX("release_date") FROM dvd_volume

Question: How many release dates does volume 4 DVD have?
SQL: SELECT COUNT("release_date") FROM dvd_volume WHERE "dvd_name" = 'Volume 4'