SQL and ALL operator

Question

Looking for an elegant way to workaround this...

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!'

The issue is that, if (SELECT ZIP FROM PEOPLE WHERE PERSONTYPE = 1) returns no records, then the above IF evaluates to true. I'm looking for a way to make this evaluate to false when there are no records returned by the ALL's subquery.

My current solution:

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

Consider using EXISTS as well.

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

Answer 2

Use:

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!'

Answer 3

Jumping in:

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!'