将 sql 表 (t1) 从一个 db (db1) 导入到另一个 (db2) (t2)，然后使用 t2 更新 db2 中表的值

Question

I need a query to import data of a table into a different table and different database. Then using the new table I need to update another table in same database

Answer 1

As you tagged SSMS, I'm assuming you're using SQL Server. This answer may apply to other databases, but you'd need to check.

How to refer to other databases

Assuming your database is on the same server, and the table is in the 'dbo' schema, then you can refer to the other database/table as follows

SELECT  *
FROM    [db1].[dbo].[t1]

If it's on a different server (but has been set up as a linked server) you can do something similar

SELECT  *
FROM    [servername].[db1].[dbo].[t1]

Making a copy of the data

To save it as a new table within your current database, you could either create a copy of the table's structure in the current database and use an INSERT INTO command, or instead let SQL Server make the table for you by using the 'INTO' clause in the SELECT eg,

SELECT   *
INTO    [db2].[dbo].[t2]     -- Or just simply [t2] if you're running this from that database and are happy with [dbo]
FROM    [db1].[dbo].[t1]

The above copies the data from the t1 table in db1 to a new table t2 in db2.

You can then use the data in t2 as you normally would use a table.

If you're running this from within d1, you will always need to refer to the tables in d2 properly (and/or alias them) as below.

UPDATE    t3
SET       xfield = t2.zfield
FROM      [db2].[dbo].[t3] AS t3
          INNER JOIN [db2].[dbo].[t2] AS t2 ON t3.id = t2.id