Question

我不确定这篇文章的标题是否正确，但我没有任何其他想法;）我有2个表 - 文档和权限。第一个是由4个属性描述的文档记录（客户，项目，文档类别，文档类型）。在第二个是由相同属性+ 用户

描述的特权记录

示例1

文档

+----+----------+---------+-------------------+---------------+
| ID | Customer | Project | Document category | Document type |
+----+----------+---------+-------------------+---------------+
|  1 | CUST1    | PROJ1   | CAT1              | TYPE1         |   
|  2 | CUST1    | PROJ2   | CAT2              | TYPE1         |
|  3 | CUST2    | PROJ1   | CAT2              | TYPE2         |
+----+----------+---------+-------------------+---------------+

权限

+----+----------+---------+-------------------+---------------+-------+
| ID | Customer | Project | Document category | Document type | User  |
+----+----------+---------+-------------------+---------------+-------+
|  1 | CUST1    |         | CAT1              |               | USER1 |
|  2 |          | PROJ1   | CAT2              |               | USER1 |
|  3 |          | PROJ1   | CAT2              |               | USER2 |
+----+----------+---------+-------------------+---------------+-------+

现在，我想从USER1的 Documents 获取与 Privileges 中的记录匹配的记录。并且有2条记录 - 来自 Documents 的ID 1和ID 3。 Documents 中的ID 1与 Privileges 中的ID 1匹配， Documents 中的ID 3与 Privileges 中的ID 2匹配。权限中的值必须相同或为空/空。

示例2

文档

+----+----------+---------+-------------------+---------------+
| ID | Customer | Project | Document category | Document type |
+----+----------+---------+-------------------+---------------+
|  1 | CUST1    | PROJ1   | CAT1              | TYPE1         |
|  2 | CUST1    | PROJ2   | CAT2              | TYPE1         |
|  3 | CUST2    | PROJ1   | CAT2              | TYPE2         |
+----+----------+---------+-------------------+---------------+

权限

+----+----------+---------+-------------------+---------------+-------+
| ID | Customer | Project | Document category | Document type | User  |
+----+----------+---------+-------------------+---------------+-------+ 
|  1 |  CUST1   |         | CAT2              |               | USER1 |
|  2 |  CUST1   | PROJ1   | CAT1              |  DTYPE2       | USER1 |
+----+----------+---------+-------------------+---------------+-------+

现在只有1条记录 - Documents 中的ID 2与 Privileges 中的ID 1匹配。'

对不起我的英文;）

Answer 1

如果我理解正确，您需要在表之间进行连接。但是，当NULL中的值为Privileges时，该字段将被忽略（即NULL暗示“全部”）。

一种方法是查询，例如：

select d.*
from documents d join
     privileges p
     on (d.customer = p.customer or p.customer is null) and
        (d.project = p.project or p.project is null) and
        (d.documentcategory = p.documentcategory or p.documentcategory is null) and
        (d.documenttype = p.documenttype or p.documenttype is null)
where p.user = 'USER1';

Answer 2

Column1 = Column2或Column2为空

  select dc.* from Documents dc join Privileges pr on 
  (dc.Customer =pr.Customer or pr.Customer is null) and 
  (dc.Project = pr.Project  or pr.Project is null) and
  (dc.Document_category = pr.Document_Category or pr.Document_Category is null)  and 
  (dc.Document_Type =pr.Document_Type or pr.Document_Type is null)
  where pr.[User]='User1'

如果你想要相等的值NULL和空（＆＃39;＆＃39;）值，请使用以下代码

Column1 = Column2或Column2为null或Column2 =＆＃39;＆＃39;

select dc.* from Documents dc join Privileges pr on 
  (dc.Customer =pr.Customer or pr.Customer is null or pr.Customer='') and
  (dc.Project = pr.Project  or pr.Project is null or pr.Project='') and
  (dc.Document_category = pr.Document_Category or pr.Document_Category is null or pr.Document_Category='')  and 
  (dc.Document_Type =pr.Document_Type or pr.Document_Type is null or pr.Document_Type='')
  where pr.[User]='User1'

比较2个表中的数据

2 个答案: