JOIN 3 tables for search

JOIN 3 tables for search

I have 3 tables: Session, Film and Vendor
Session.FilmID
Film.VendorID
Vendor.VendorName
I want to include the VendarName in the search.
Here's what I have:
sql ="SELECT SessionID, Identifier, SessionType.SessionTypeName, Film.*,
Vendor.*,
CameraID, Date FROM Session "
sql = sql + "JOIN SessionType USING (SessionTypeID) "
sql = sql + "JOIN Film USING(FilmID) "
sql = sql + "JOIN Vendor ON Film.VendorID = Vendor.VendorID "
sql = sql + "WHERE Session.Identifier LIKE ('%" + search + "%') OR "
sql = sql + "Session.Notes LIKE('%" + search + "%') OR "
sql = sql + "SessionType.SessionTypeName LIKE ('%" + search + "%') "
sql = sql + "Film.Vendor.VendorName LIKE ('%" + search + "%') "
sql = sql + "ORDER BY Identifier,SessionType.SessionTypeName"
What am I doing wrong?