Posted By: jerryiii (Vsude dobre, v CR nejhur) on 'CZdatabases' Title: Re: dotaz na dotaz ;) Date: Thu Jun 19 19:55:05 2003 > > Ahoj, > tusite nekdo, jak zjistit, zda mnozina obsahuje vsechny prvku jine mnoziny? > > Konkretne dotaz: Which shops offer all of the cheeses made in the UK? > > Pricemz vsechny syry z UK jsou SELECT Name FROM Cheese WHERE Origin='UK'. > Zkousel jsem ruzne variace na tema > > SELECT Shop FROM sells WHERE Cheese =ALL (ten dotaz vyse), > > ale nejak jsem nebyl uspesny. Ani s >=ALL apod. (ta mnozina muze obsahovat > i jine, dulezite je, aby obsahovala vsechny urcene). > > Diky moc za jakoukoliv radu... a cim drive, tim lepe. ;) SELECT Shop FROM sells WHERE COUNT(DISTINCT Cheese) = (SELECT COUNT(DISTINCT Name FROM Cheese WHERE Origin = 'UK') Pricemz by ten vnorenej dotaz mohl byt i COUNT(*) a mohl bys vynechat ty DISTINCT podle toho jak mas navrhnutou databazi. A mozna na konci jeste musi byt GROUP BY Shop (vice mene kombinace sloupcu ktera jednoznacne identifikuje kram, zase zalezi na DB). > Diiiiky > > > JiMo:) > > CONNECT 300^M .....OP^aFD)*HR!hT%UJ0~~!aS&RT&*WQ$*brI&FG^NO CARRIER Jerry III Enough said ... http://jerryiii.home.sprynet.com/mica/index.htm