Sql 如何连接来自不同数据库的多个表？

如何编写选择查询，从不同的表和数据库中选择值

e、 g

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我的主要目标是加入所有表

我相信这通常会起作用：

SELECT ...
FROM dbSALES.tbSalesOrder
JOIN dbSHIPMENT.tbShipmentDetails ON ...
JOIN dbSHIPMENT.tbShipmentMaster ON ...

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假设您正在使用SQL Server

它将使用普通的SELECT with JOIN编写，但使用完全限定的表名，如database.schema.object\u name。像这样：

SELECT
  ...
FROM dbSALES.tbSalesOrder
INNER JOIN dbSHIPMENT.tbShipmentDetails ...

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在SQL Server中，您可以使用以下内容：

SELECT [column-list] FROM dbSales.[schema].tbSalesOrder SO JOIN dbSHIPMENT.[schema].tblShipmentDetails SD ON SD.[join_column] = SO.[join_column] JOIN dbSHIPMENT.[schema].tbShipmentMaster SM ON SM.[join_column] = SD.[join column] 试试这个

select * from dbSales.tbSalesOrder a
         join dbShipment.tbShipmentDetails b on (a.field1=b.field1 and ......)
         join dbShipment.tbShipmentMaster c on (b.field1=c.field1 and ......)
where a.field1=xxxx and b.field2=yyyy

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您正在使用什么RDBMS？？

select * from dbSales.tbSalesOrder a
         join dbShipment.tbShipmentDetails b on (a.field1=b.field1 and ......)
         join dbShipment.tbShipmentMaster c on (b.field1=c.field1 and ......)
where a.field1=xxxx and b.field2=yyyy