Problem Statement

Write a function/procedure/subroutine that is called with an integer value and returns the middle three digits of the integer if possible or a clear indication of an error if this is not possible. Note: The order of the middle digits should be preserved. Your function should be tested with the following values; the first line should return valid answers, those of the second line should return clear indications of an error: Show your output on this page.

Let's start with the solution:

;WITH DATA 
     AS (SELECT CAST(ABS(NUMBER) AS NVARCHAR(MAX))      charNum, 
                NUMBER, 
                LEN(CAST(ABS(NUMBER) AS NVARCHAR(MAX))) LcharNum 
         FROM   TABLE1) 
SELECT CASE 
         WHEN ( LCHARNUM >= 3 
                AND LCHARNUM % 2 = 1 ) THEN SUBSTRING(CHARNUM, LCHARNUM / 2, 3) 
         ELSE 'Error!' 
       END    Output, 
       NUMBER Input 
FROM   DATA