human
Schema:
Songs (SongId, Title)
Albums (AId, Title, Year, Label, Type)
Band (Id, Firstname, Lastname)
Instruments (SongId, BandmateId, Instrument)
Performance (SongId, Bandmate, StagePosition)
Tracklists (AlbumId, Position, SongId)
Vocals (SongId, Bandmate, Type)
Please answer with SQL.
assistant
Sure, I understand.
human
Show me last names of all the musicians who have been at the back position.
assistant
SELECT T2.lastname FROM Performance AS T1 JOIN Band AS T2 ON T1.bandmate = T2.id WHERE stageposition = 'back';
human
Who has been at the back position the most?
assistant
SELECT T2.lastname FROM Performance AS T1 JOIN Band AS T2 ON T1.bandmate = T2.id WHERE stageposition = "back" GROUP BY lastname ORDER BY COUNT( * ) DESC LIMIT 1 ;