#NEWLINE# def distinct_sql( self , fields ) : #NEWLINE# #INDENT# '\n        Returns an SQL DISTINCT clause which removes duplicate rows from the\n        result set. If any fields are given, only the given fields are being\n        checked for duplicates.\n        ' #NEWLINE# if self : #NEWLINE# #INDENT# raise NotImplementedError ( 'DISTINCT ON fields is not supported by this database backend' ) #NEWLINE# #UNINDENT# else : #NEWLINE# #INDENT# return 'DISTINCT'