Question

I am trying to write a validation for the following set of data:

SSYS | Material_Number | Characteristic | Description
001  | 000000000001111 | SH_DESC        | TEST
001  | 000000000001111 | DESIGN_TYPE    | NULL
001  | 000000000001111 | VOLTAGE        | NULL
001  | 000000000009999 | SH_DESC        | TEST2
001  | 000000000009999 | OPER_METHOD    | LIGHT
001  | 000000000009999 | FILTER_TYPE    | Filter element,Air
001  | 000000000014560 | SH_DESC        | Horn,Signal
001  | 000000000014560 | DIMENSION_SIZE | NULL
001  | 000000000014560 | FILTER_TYPE    | NULL

I would like to group by the Material_Number and count as 1 (ie. true) if within the Material_Number group, the SH_DESC description is NOT NULL and all other characteristics’ descriptions IS NULL. So, in this case my result would be:

SSYS | Material_Number | Characteristic | Description  | COUNT
001  | 000000000001111 | SH_DESC        | TEST         |  1
001  | 000000000009999 | SH_DESC        | TEST2        |  0 
001  | 000000000014560 | SH_DESC        | Horn,Signal  |  1

My attempt:

Select COUNT (*), SSYS, Material_Number, Characteristic, Description
 From myDB where (Characteristic = 'SH_DESC' AND DESCRIPTION IS NOT NULL) AND (Characteristic NOT IN ('SH_DESC') IS NULL)
GROUP BY SSYS, Material_Number, Characteristic, Description HAVING COUNT (*) < 2

Any help is much appreciated!

Answer 1

Try:

Select SSYS, 
       Material_Number, 
       'SH_DESC' Characteristic, 
       MAX(CASE WHEN Characteristic = 'SH_DESC' THEN Description END) Description,
       CASE WHEN MAX(CASE WHEN Characteristic = 'SH_DESC' THEN Description END) IS NOT NULL AND
                 MAX(CASE WHEN Characteristic <>'SH_DESC' THEN Description END) IS NULL 
            THEN 1
            ELSE 0
       END COUNT
From myDB
GROUP BY SSYS, Material_Number