Sql 根据第三个表中的值查找不存在的位置

我有一个名为

Cities

的表，如下所示：

+--------+-------------+-------+----------+------------+
| CityID |    City     | State | TimeZone | UserAccess |
+--------+-------------+-------+----------+------------+
|      1 | Albany      | NY    |        4 |          1 |
|      2 | Allentown   | PA    |        6 |          1 |
|      3 | Albuquerque | NM    |        4 |          1 |
|      4 | Amarillo    | TX    |        3 |          1 |
|      5 | Atlanta     | GA    |        4 |          1 |
+--------+-------------+-------+----------+------------+

+--------+----------+
| CityID | RegionID |
+--------+----------+
|      1 |       14 |
|      1 |       15 |
|      2 |       14 |
|      3 |       11 |
|      4 |       12 |
|      4 |       13 |
|      5 |       12 |
|      5 |       13 |
+--------+----------+

+----------+-----------+--------+
| RegionID |  Region   | TypeID |
+----------+-----------+--------+
|       10 | West      |      1 |
|       11 | West      |      2 |
|       12 | South     |      1 |
|       13 | South     |      2 |
|       14 | Northeast |      1 |
|       15 | Northeast |      2 |
+----------+-----------+--------+

我有另一个名为

CitiesToRegions

的表，如下所示：

+--------+-------------+-------+----------+------------+
| CityID |    City     | State | TimeZone | UserAccess |
+--------+-------------+-------+----------+------------+
|      1 | Albany      | NY    |        4 |          1 |
|      2 | Allentown   | PA    |        6 |          1 |
|      3 | Albuquerque | NM    |        4 |          1 |
|      4 | Amarillo    | TX    |        3 |          1 |
|      5 | Atlanta     | GA    |        4 |          1 |
+--------+-------------+-------+----------+------------+

+--------+----------+
| CityID | RegionID |
+--------+----------+
|      1 |       14 |
|      1 |       15 |
|      2 |       14 |
|      3 |       11 |
|      4 |       12 |
|      4 |       13 |
|      5 |       12 |
|      5 |       13 |
+--------+----------+

+----------+-----------+--------+
| RegionID |  Region   | TypeID |
+----------+-----------+--------+
|       10 | West      |      1 |
|       11 | West      |      2 |
|       12 | South     |      1 |
|       13 | South     |      2 |
|       14 | Northeast |      1 |
|       15 | Northeast |      2 |
+----------+-----------+--------+

我有一个

区域

表，如下所示：

+--------+-------------+-------+----------+------------+
| CityID |    City     | State | TimeZone | UserAccess |
+--------+-------------+-------+----------+------------+
|      1 | Albany      | NY    |        4 |          1 |
|      2 | Allentown   | PA    |        6 |          1 |
|      3 | Albuquerque | NM    |        4 |          1 |
|      4 | Amarillo    | TX    |        3 |          1 |
|      5 | Atlanta     | GA    |        4 |          1 |
+--------+-------------+-------+----------+------------+

+--------+----------+
| CityID | RegionID |
+--------+----------+
|      1 |       14 |
|      1 |       15 |
|      2 |       14 |
|      3 |       11 |
|      4 |       12 |
|      4 |       13 |
|      5 |       12 |
|      5 |       13 |
+--------+----------+

+----------+-----------+--------+
| RegionID |  Region   | TypeID |
+----------+-----------+--------+
|       10 | West      |      1 |
|       11 | West      |      2 |
|       12 | South     |      1 |
|       13 | South     |      2 |
|       14 | Northeast |      1 |
|       15 | Northeast |      2 |
+----------+-----------+--------+

我试图做的是编写一个查询，以便根据

Regions

表的

TypeID

查看缺少

CitiesToRegions

指定的位置。到目前为止，我得到的结果是什么都不返回，我确信这是因为我的第一个join没有找到空值，因为

CityID

分配了

RegionID

。我就是不知道如何写下我想要的东西

SELECT DISTINCT Cities.CityID
FROM Cities
    INNER JOIN CitiesToRegions on Cities.CityID = CitiesToRegions.CityID
    FULL JOIN Regions on CitiesToRegions.RegionID = Regions.RegionID
WHERE (CitiesToRegions.RegionID is null) AND (Cities.UserAccess=1) AND (Regions.TypeID != 1)

对于查询结果，我希望看到的是以下内容，因为它是唯一一个没有

RegionID的
城市ID

+--------+
| CityID |
+--------+
|      3 |
+--------+

注意：我不想看到2中缺少的
TypeID
，因为我会运行相同的查询，并将
TypeID
作为变量传入：
以下内容应该满足您的需要-我发现
不存在
子查询更清楚地获得正确的逻辑，然后是复杂的连接

select *
from Cities C
where not exists (
  select 1
  from CitiesToRegions CR
  inner join Regions R on CR.RegionID = R.RegionID and R.TypeID = 1
  where CR.CityID = C.CityID
)

CitiesToRegions.RegionID对于该数据和这些联接永远不会为空。Cities和CitiesToRegions之间的内部连接意味着所有这些都将匹配，而与Regions的完全连接是毫无意义的，因为您仍然需要匹配Cities值。我可能会使用
notexists
子句而不是join。