跨多个数据库连接查询 - 语法错误

Question

我有 2 个数据库，即 db1、db2。我需要一个从这些 dbs(db1,db2) 中获取数据的查询，这些 dbs(db1,db2) 每个都有 2 个表（让步，发票）。

在 db1.concessions => 让步是主键。 db1.invoicing => [Concession Number] 是主键

同样在 db2.concessions => 让步是主键。 db2.invoicing => [Concession Number] 是主键

在数据库1中

db1.tbl1 => 优惠表有数据

    concession
    TH-123
    TH-456
    FP-789
    NZ-609

db1.tbl2 => 发票表有数据

    [Concession Number]          invoiced_on
    TH-322                        10.09.10
    TH-900                        23.10.10
    FP-675                        04.05.09
    NZ-111                        19.11.08

幸运的是，在数据库中，让步的值是唯一的。即让步。[让步] = 发票。[让步号] 不产生任何数据..

在数据库 2 中：

db1.tbl1 => 优惠表有数据

    concession
    TH-123
    FP-789
    NZ-999
    TH-900

db1.tbl2 => 发票表有数据

    [Concession Number]          invoiced_on(dd.mm.yy)
    TH-456                        18.01.06
    TH-777                        23.10.04
    FP-675                        03.05.09
    NZ-149                        26.11.08

这里在 db2 让步是唯一的，让步。[让步] = 开票。[让步号] 不产生任何数据..

现在查询应该获取有共同点的记录 db1.(concessions.concession OR invoicing.concession number) = db2(concessions.concession OR invoicing.concession number)

在它应该返回的样本数据中，TH-123、FP-789、NZ-999、FP-675。

我的第二个问题是有可能将此查询扩展到多个数据库。我无法将数据库的计数更改为 1，因为它们已经固定。请让我知道相同的最佳程序。

我试过这样的，有语法错误，

SELECT a.concession as db1_CON_NUMBER FROM db1.dbo.concessions as a  UNION 
SELECT b.[Concession Number] as db1_CON_NUMBER  FROM db1.dbo.invoicing as b 
INNER JOIN 
SELECT c.concession as db2_CON_NUMBER FROM db2.dbo.concessions as c  UNION 
SELECT d.[Concession Number] as db2_CON_NUMBER  FROM db2.dbo.invoicing as d 
ON db1_CON_NUMBER = db2_CON_NUMBER 

希望您能回答这两个问题。 感谢您耐心阅读这么长的邮件！

Answer 1

如果用户有权限，可以直接引用其他数据库。

<database>.<user>.<tablename>

是数据库表的完整“路径”。

你经常使用

db1.dbo.tbl1 join db2.dbo.tbl2

其中 dbo 是数据库所有者的默认值，任何不属于特定用户的表默认归 dbo 所有。

UPDATE

要让查询验证，您可以将其扩展至此

SELECT * FROM 
(SELECT a.concession as db1_CON_NUMBER FROM db1.dbo.concessions as a  
UNION 
SELECT b.[Concession Number] as db1_CON_NUMBER FROM db1.dbo.invoicing as b ) c

INNER JOIN 

(SELECT c.concession as db2_CON_NUMBER FROM db2.dbo.concessions as a 
UNION 
SELECT b.[Concession Number] as db2_CON_NUMBER FROM db2.dbo.invoicing as b ) d

ON db1_CON_NUMBER = db2_CON_NUMBER 

但我没有时间检查这是否会返回正确的数据，但您可以测试。

Answer 2

如果数据库在同一个 SQL Server 实例上，您可以使用 3 部分命名：

database_name.schema_name.object_name

Using Identifiers As Object Names

如果数据库不在同一个实例上，创建一个链接服务器：Linked Servers

Creating Linked Servers (SQL Server Database Engine)

链接服务器允许访问 分布式异构查询 针对 OLE DB 数据源。之后 链接服务器已创建、分发 可以对此运行查询 服务器，查询可以连接表 来自多个数据源。如果 链接服务器被定义为 SQL Server 实例，远程存储 程序可以执行。

Answer 3

select * from(
SELECT a.concession as db1_CON_NUMBER FROM BABMwork6_5_3108.dbo.concessions as a  
        WHERE (a.manuell_archive_delete! = 'Delete' OR  a.manuell_archive_delete IS NULL) 
UNION SELECT b.[Concession Number] as db1_CON_NUMBER  FROM BABMwork6_5_3108.dbo.invoicing as b) as tbl1 
INNER JOIN 
(SELECT c.concession as db2_CON_NUMBER FROM BABMwork6_6_2909.dbo.concessions as c  
        WHERE (c.manuell_archive_delete! = 'Delete' OR  c.manuell_archive_delete IS NULL) 
UNION SELECT d.[Concession Number] as db2_CON_NUMBER  FROM BABMwork6_6_2909.dbo.invoicing as d ) as tbl2
ON tbl1.[db1_CON_NUMBER] = tbl2.[db2_CON_NUMBER]