There're no another ways? It don't looks like optimal. Petr Jezek ----- Original Message ----- From: "Jean-Luc Lachance" <[EMAIL PROTECTED]> To: "Roy Souther" <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]> Sent: Monday, July 08, 2002 5:22 PM Subject: Re: [SQL] Bad SUM result
> That is because your query is generating a cartesian product. > > Try: > > SELECT ( > SELECT SUM(totalprice) > FROM invoices > WHERE custnumber = '1' > ) - ( > SELECT SUM(paymentamount) > FROM payments > WHERE custnumber = '1' > ) > > > > Roy Souther wrote: > > > > -----BEGIN PGP SIGNED MESSAGE----- > > Hash: SHA1 > > > > I have an invoice database that has two tables one for invoices and one for > > payments. I want to get the account balance for a client by subtracting the > > sum of all payments from the sum off all invoices for that client. > > > > Here is the SQL that I thought should work. > > SELECT SUM(t0.totalprice)-SUM(t1.paymentamount) FROM invoices t0, payments t1 > > WHERE t0.custnumber='1' AND t1.custnumber='1' > > > > It works fine if there is only one invoice and one payment but as soon as > > there is more then one of either it screws up. For each match found in > > payments the invoice sum is added to the total. So if client 1 purchased a > > $100 item then maid a $10 payment the SQL would return the balance of $90 > > just fine. When the client makes a second payment of $15 the balance is $75 > > but this SQL returns ($100+$100)-($10+$15) = $175. A third payment of $1 > > would return ($100+$100+$100)-($10+$15+$1) = $274. > > > > Could some one explain this to me and recommend an SQL command that would work > > please? I could do this using a temp table but that would be very messy as I > > would really like it to be a single SQL command. > > - -- > > Roy Souther <[EMAIL PROTECTED]> > > http://www.SiliconTao.com > > > > Linux: May the source be with you. > > > > -----BEGIN PGP SIGNATURE----- > > Version: GnuPG v1.0.6 (GNU/Linux) > > Comment: For info see http://www.gnupg.org > > > > iEYEARECAAYFAj0oo9MACgkQCbnxcmEBt43qFQCgtjCs7khKGH+2LYd78O9mA3h4 > > vDQAn0GkKkuYl1Kybgm/ITO4LbO1WWLX > > =1G4R > > -----END PGP SIGNATURE----- > > > > ---------------------------(end of broadcast)--------------------------- > > TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED] > > > > ---------------------------(end of broadcast)--------------------------- > TIP 6: Have you searched our list archives? > > http://archives.postgresql.org > ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
