SQL Server-比较同一表中的值

Question

在SQL Server中，我有一个包含以下数据（tblUserSettings）的表：

| 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      |

我需要将CityID = 20的所有UserTypes的所有值与CityID = 3的对应UserTypes的所有值进行比较。CountryID =9。要比较的列是：Value1，Value2，Value3。

我只需要知道它们是否彼此匹配即可。 我尝试执行以下操作：

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

它给了我以下结果，我必须进一步处理以定义是否所有内容都匹配。

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

我能以某种方式使输出中只有一列和一行吗？-对于所有匹配项，只接收1；如果至少一个不匹配，则只接收0？

Answer 1

如果您希望在所有值都匹配时只获得包含1一列，如果不匹配则返回0 ，请使用，

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

如果您想比较所有城市而不只是两个城市，则应该能够通过分组而不是加入来进行比较。

就像是：

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