Re: Comparing dates - Mailing list pgsql-sql
From | Michael Fork |
---|---|
Subject | Re: Comparing dates |
Date | |
Msg-id | Pine.BSI.4.21.0103061007320.17993-100000@glass.toledolink.com Whole thread Raw |
In response to | Comparing dates (Markus Fischer <mfischer@josefine.ben.tuwien.ac.at>) |
List | pgsql-sql |
I am just wildly guessing here, but you initially stated that you queried on '02-03-2001' (Which I read as February 3, 2001 -- and I belive postgres does as well) which returned 60 results, and on '03-03-2001' (March 3, 2001), which returned 70 results. However, that is *not* the query your wrote out, you wrote date_date >= '2001-03-02' (which I would read as March 2, 2001) and date_date <= '2001-03-03' (March 3, 2001) -- which is two entirely different date ranges, and, hence, why you see the seemingly incorrect results. Try this: SELECT count(*) FROM table WHERE date_date = '03-02-2001'::date; SELECT count(*) FROM table WHERE date_date = '03-03-2001'::date; The sum of the above two, should match the count for each of the next two SELECT count(*) FROM table WHERE date_date >= '03-02-2001'::date AND date_date <= '03-03-2001'::date; SELECT count(*) FROM table WHERE date_date >= '03-02-2001'::date AND date_date < '03-04-2001'::date; Michael Fork - CCNA - MCP - A+ Network Support - Toledo Internet Access - Toledo Ohio On Tue, 6 Mar 2001, Markus Fischer wrote: > Hello, > > I've a SELECT statement on many joined Tabled and one of them has > a date column called 'date_date'. When I fetch a date e.g. > '02-03-2001', I get, say, 60 results back. When I now perform the > same query with another date, lets take '03-03-2001', I get back > about 70 results. > > When I now modify my query to get both results in one I write > > SELECT > .... > FROM > .. > AND > date_date >= '2001-03-02' > AND > date_date <= '2001-03-03' > AND > .... > > I think I should get back the rows for both days, 60 + 70 makes > 130 to me. But what I get back is even smaller then 60. I > allready tried TO_DATE conversion, an OR construct but always > the same result. > > Is there something special to know when comparing/working with > date-datetypes ? > > > kind regards, > Markus > > -- > Markus Fischer, http://josefine.ben.tuwien.ac.at/~mfischer/ > EMail: mfischer@josefine.ben.tuwien.ac.at > PGP Public Key: http://josefine.ben.tuwien.ac.at/~mfischer/C2272BD0.asc > PGP Fingerprint: D3B0 DD4F E12B F911 3CE1 C2B5 D674 B445 C227 2BD0 > > ---------------------------(end of broadcast)--------------------------- > TIP 2: you can get off all lists at once with the unregister command > (send "unregister YourEmailAddressHere" to majordomo@postgresql.org) >