Hi, This particular case can be handled by a special case of the inner equijoin.
> ( recommend_ratings2.movieid = T_0.movieid_0 or >((recommend_ratings2.movieid IS NULL) AND (T_0.movieid_0 IS NULL))) Can be rewritten as a null-safe equi-join (i.e where movieid <=> movieid_0, which is not SQL semantics). That however is a corner-case to workaround folks who want OR joins to just handle NULL == NULL as a match. Cheers, Gopal
