SQL et ALL opérateur

Question

Vous cherchez une façon élégante de contourner ce ...

DECLARE @ZIP INT 
SET @ZIP = 55555 

IF @ZIP = ALL(SELECT ZIP FROM PEOPLE WHERE PERSONTYPE = 1) 
    PRINT 'All people of type 1 have the same zip!' 
ELSE 
    PRINT 'Not All people of type 1 have the same zip!' 

Le problème est que, si (SELECT postal DE PERSONNES OU PersonType = 1) ne renvoie aucun enregistrement, alors ce qui précède IF evalue à vrai. Je cherche un moyen de rendre cette évaluation à false quand il n'y a pas d'enregistrements retournés par la sous-requête ALL.

Ma solution actuelle:

DECLARE @ZIP INT 
SET @ZIP = 55555 

DECLARE @ALLZIPS TABLE (INT ZIP) 

INSERT INTO @ALLZIPS 
SELECT ZIP FROM PEOPLE WHERE PERSONTYPE = 1 

IF EXISTS(SELECT TOP 1 * FROM @ALLZIPS) AND (@ZIP = ALL (SELECT ZIP FROM @ALLZIPS)) 
    PRINT 'All people of type 1 have the same zip!' 
ELSE 
    PRINT 'Not All people of type 1 have the same zip!' 

Answer 1

Sauter dans:

IF (SELECT SUM(CASE WHEN ZIP = @ZIP THEN 0 ELSE 1 END) 
    FROM PEOPLE WHERE PERSONTYPE = 1) = 0 
    PRINT 'All people of type 1 have the same zip!' 
ELSE 
    PRINT 'Not All people of type 1 have the same zip!' 

Answer 2

Pensez à utiliser EXISTE ainsi.

IF @ZIP = ALL(SELECT ZIP FROM PEOPLE WHERE PERSONTYPE = 1) 
    AND EXISTS(SELECT 1 FROM PEOPLE WHERE PERSONTYPE = 1) 

Answer 3

Utilisation:

IF EXISTS(SELECT NULL 
      FROM PEOPLE p 
      WHERE p.persontype = 1 
      HAVING MIN(p.zip) = @Zip 
      AND MAX(p.zip) = @Zip) 
    PRINT 'All people of type 1 have the same zip!' 
ELSE 
    PRINT 'Not All people of type 1 have the same zip!'