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
How many songs do not have a back vocal?
assistant
SELECT COUNT( DISTINCT title ) FROM vocals AS t1 JOIN songs AS t2 ON t1.songid = t2.songid EXCEPT SELECT t2.title FROM vocals AS t1 JOIN songs AS t2 ON t1.songid = t2.songid WHERE TYPE = "back" ;