SQL Server-比较同一表中的值

Question

In SQL Server, I have one table with following data (tblUserSettings):

| CountryID | CityID  | UserType | Value1 | Value2 | Value3 |
| 9         | 3       | 1        | 5      | 5      | 5      |
| 9         | 3       | 2        | NULL   | NULL   | NULL   |
| 9         | 3       | 3        | 5      | 5      | 5      |
| 9         | 3       | 4        | 5      | 5      | 5      |
| 9         | 20      | 1        | 5      | 5      | 5      |
| 9         | 20      | 2        | NULL   | NULL   | NULL   |
| 9         | 20      | 3        | 5      | 5      | 5      |
| 9         | 20      | 4        | 0      | 0      | 0      |

I need to compare all the values for all UserTypes from CityID = 20 with all the values for corresponding UserTypes from CityID = 3. The CountryID = 9. The columns to compare are: Value1, Value2, Value3.

I just need to know if all of them are matched to each other or not. I tried to do something as follows:

SELECT CASE WHEN ISNULL(t1.Value1, 0) = ISNULL(t2.Value1, 0) THEN 1 ELSE 0 END AS Match1,
        CASE WHEN ISNULL(t1.Value2, 0) = ISNULL(t2.Value2, 0) THEN 1 ELSE 0 END AS Match2,
        CASE WHEN ISNULL(t1.Value3, 0) = ISNULL(t2.Value3, 0) THEN 1 ELSE 0 END AS Match3
FROM tblUserSettings t1
INNER JOIN tblUserSettings t2 ON t1.CountryID = t2.CountryID 
           AND t1.UserType = t2.UserType
           AND t1.CityID = 3
           AND t2.CityID = 20
WHERE t1.CountryID = 9

And it gives me following result which I have to process further to define if everything matches or not.

| Match1 | Match2  | Match3 |
| 1      | 1       | 1      |
| 1      | 1       | 1      |
| 1      | 1       | 1      |
| 0      | 0       | 0      |

Can I do this in a way to have only one column and row in output - just receive either 1 for all the matches or 0 if at least one doesn't match?

Answer 1

If you are looking to get only one column with 1 when all the values match and 0 if atleast one doesn't, use,

SELECT 
CASE WHEN ISNULL(t1.Value1, 0) = ISNULL(t2.Value1, 0) 
      AND ISNULL(t1.Value2, 0) = ISNULL(t2.Value2, 0) 
      AND ISNULL(t1.Value3, 0) = ISNULL(t2.Value3, 0) 
THEN 1 ELSE 0 END AS Match
FROM tblUserSettings t1
INNER JOIN tblUserSettings t2 ON t1.CountryID = t2.CountryID 
           AND t1.UserType = t2.UserType
           AND t1.CityID = 3
           AND t2.CityID = 20
WHERE t1.CountryID = 9

Answer 2

If you are looking to compare all cities rather than just two you should be able to do this by grouping rather than joining.

Something like:

SELECT 
CASE WHEN
       max(Value1)-min(Value1) = 0
       AND max(Value2)-min(Value2) = 0
       AND max(Value3)-min(Value3) = 0
THEN 1 ELSE 0 AS Match
FROM tblUserSettings
GROUP BY CountryID,UserType