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