Mysql dziwne zachowanie OR Opcje

[skowron-line]

Wiam, mam takie 2 tabele

Kod

invoice
-buyer_id
-paid 0 - niezaplacone, 1 - zaplacone

companies
-id_companies

i zapytanie

[SQL] pobierz, plaintext 
SELECT
invoices.buyer_id, invoices.companies_id, companies.id_companies
FROM (invoices, companies)
WHERE invoices.buyer_id = companies.id_companies
AND 
(
    MONTH(invoices.invoice_date) = '8' 
    AND YEAR(invoices.invoice_date) = '2012'
)
OR
(
    invoices.payment_date < '2012-8-01' 
    AND invoices.paid = 0
)
AND invoices.companies_id = 1
[SQL] pobierz, plaintext 

i teraz tak
Jeżeli tylko 1 część jest zgodna to zwraca 2 rekordy z pominięciem ostatniego warunku

[SQL] pobierz, plaintext 
invoices.companies_id = 1
[SQL] pobierz, plaintext 

Jeżęli w bazie są rekordy zgodne z drugim nawiasem to zapytanie zwraca mi tyle rekordów ile jest w tabeli companies.

Co tu jest nie tak (IMG:style_emoticons/default/questionmark.gif)

[maly_swd]

A nie powinno byc tak?

[SQL] pobierz, plaintext 
SELECT
invoices.buyer_id, invoices.companies_id, companies.id_companies
FROM (invoices, companies)
WHERE invoices.buyer_id = companies.id_companies
AND (
( MONTH(invoices.invoice_date) = '8'  AND YEAR(invoices.invoice_date) = '2012')
OR
( invoices.payment_date < '2012-8-01' AND invoices.paid = 0)
) AND invoices.companies_id = 1
[SQL] pobierz, plaintext 

Ten post edytował maly_swd 27.06.2012, 20:24:30