Can we use the join operation for two tables from different databases? If yes, then how to do ?
我们可以对来自不同数据库的两个表使用join操作吗?如果是，怎么做?
Both databases are on the same server and DBMS is the same.
这两个数据库都位于同一个服务器上，而DBMS是相同的。
2 个解决方案
#1
118
SQL Server allows you to join tables from different databases as long as those databases are on the same server. The join syntax is the same; the only difference is that you must fully specify table names.
SQL Server允许您连接来自不同数据库的表，只要这些数据库位于同一服务器上。连接语法是相同的;惟一的区别是必须完全指定表名。
Let's suppose you have two databases on the same server - Db1 and Db2. Db1 has a table called Clients with a column ClientId and Db2 has a table called Messages with a column ClientId (let's leave asside why those tables are in different databases).
假设在同一个服务器上有两个数据库——Db1和Db2。Db1有一个名为client的表，其中包含一个列ClientId，而Db2有一个名为Messages的表，其中包含一个列ClientId(让我们来说明为什么这些表位于不同的数据库中)。
Now, to perform a join on the above-mentioned tables you will be using this query:
现在，要对上述表执行连接，您将使用以下查询:
select *
from Db1.dbo.Clients c
join Db2.dbo.Messages m on c.ClientId = m.ClientId
#2
0
SELECT ...
FROM A.table t1
JOIN B.table2 t2 ON t2.column = t1.col
#1
118
SQL Server allows you to join tables from different databases as long as those databases are on the same server. The join syntax is the same; the only difference is that you must fully specify table names.
SQL Server允许您连接来自不同数据库的表，只要这些数据库位于同一服务器上。连接语法是相同的;惟一的区别是必须完全指定表名。
Let's suppose you have two databases on the same server - Db1 and Db2. Db1 has a table called Clients with a column ClientId and Db2 has a table called Messages with a column ClientId (let's leave asside why those tables are in different databases).
假设在同一个服务器上有两个数据库——Db1和Db2。Db1有一个名为client的表，其中包含一个列ClientId，而Db2有一个名为Messages的表，其中包含一个列ClientId(让我们来说明为什么这些表位于不同的数据库中)。
Now, to perform a join on the above-mentioned tables you will be using this query:
现在，要对上述表执行连接，您将使用以下查询:
select *
from Db1.dbo.Clients c
join Db2.dbo.Messages m on c.ClientId = m.ClientId
#2
0
SELECT ...
FROM A.table t1
JOIN B.table2 t2 ON t2.column = t1.col