"sasha" <[EMAIL PROTECTED]> wrote: > > Äåëî â òîì ÷òî ÿ âûïîëíÿþ: > > DELETE FROM "RssFeedItemCategories" C > WHERE NOT EXISTS(SELECT * FROM "RssFeedItems" I WHERE I."Id" = > C."FeedItemId") > > è > > DELETE FROM "RssFeedItemCategories" C > WHERE C."FeedItemId" <> SOME(SELECT "Id" FROM "RssFeedItems" I)
Âîîáùå ðàçíûå ïðåäèêàòû. Âî âòîðîì ñëó÷àå óäàëåíèå ïðîèñõîäèò, åñëè FeedItemId íåðàâåí õîòÿ áû îäíîìó èç çíà÷åíèé Id. À ýòî óñëîâèå âñåãäà èñòèííî. NOT EXISTS ïîõîæ íà NOT IN (åñëè íóëëîâ â ïîëå ãàðàíòèðîâàííî íåò), êîòîðûé ñóòü åñòü "NOT value = SOME". Íî ýòî ýêâèâàëåíòíî "value <> ALL", à îòíþäü íå "value <> SOME", êàê òû íàïèñàë âûøå. -- Äìèòðèé Åìàíîâ
