T E Schmitz <[EMAIL PROTECTED]> writes: > Greg Stark wrote: >> Which book is it?
> PostgreSQL by Korry Douglas + Susan Douglas, ISBN 0-7357-1257-3; Feb 2003 Hmm, I've heard of that book but never seen it. The authors are not participants in the PG community --- AFAICT neither of them have ever posted anything in the mailing lists. > The paragraph continues: > "If the SELECT command included the clause WHERE phone NOT NULL, > PostgreSQL could use the index to satisfy the ORDER BY clause. > An index that covers optional (NOT NULL) columns will not be used to > speed table joins either." My goodness, it seems to be a veritable fount of misinformation :-( I wonder how much of this is stuff that is true for Oracle and they just assumed it carried over? regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org