> From: David Fetter [mailto:david@xxxxxxxxxx] > On Tue, Sep 11, 2007 at 08:55:53AM -0700, George Pavlov wrote: > > sum(case when z!=0 then 1 end) as good, > > This case statement returns true when z factorial is zero, so I'd > recommend the SQL standard <> or IS NOT DISTINCT FROM instead. and what would be that number that has its factorial = 0 ?! (just giving you a hard time this not being a math forum...) thanks dave, you do bring a valid point of there being ambiguity about the ! and that might be worth noting in the manual (http://www.postgresql.org/docs/8.2/interactive/functions-comparison.htm l). however, it seems that our favorite DBMS does the right thing and gives precedence to the != as "not equal", so taking a more realistic example (non-zero factorials): foo=> select 2 != 2; ?column? ---------- f (1 row) foo=> select 2 <> 2; ?column? ---------- f (1 row) foo=> select (2 !)= 2; ?column? ---------- t (1 row) i do hate potential ambiguity... the != was something stuck in my brain from old sybase, i think. i always liked != ("not equals") as more intuitive than <> ("less than, greater than"???), but i will have to change my ways, especially if "the standard" says so. ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to majordomo@xxxxxxxxxxxxxx so that your message can get through to the mailing list cleanly
