Merging multiple databases into one

Question

SQL

There is a need to combine several databases (11) into one. All databases are located on different servers scattered across Russia.
Firstly, I can’t decide how to transfer data (Mail, ftp, something else?)
Secondly, only one tablet needs to be obtained from each of the databases. But the fact is that in each database we have in the tables the same fields with the same values, in no case should they be deleted. can be renamed.
The system works as follows.
There is a center for example Ikea.
It contains sensors that send numerical data to the database. Each sensor in the database has its own id. logentid. There are many such centers and these fields are similar everywhere. but the names of the sensors are different.
Example:
1) Center 1 Sensor 1 - id 10 - logentid 1212 - readings from sensor 12
2) Center 2 Sensor 1 - id 10 - logentid 1542 - readings from sensor 11
3) Center 3 Sensor 1 - id 11 - logentid 1212 - readings from sensor 18
etc .d.
The problem is that id and Logentid can match and then a huge confusion will begin. because data will be assigned to other sensors.
You need to do something like this:
The program read the data from the sensor, wrote it to the database.
From the database, the request unloaded data into a file.
The file was sent to the central server (Mail, ftp, ....)
There, this file was uploaded to the central database.
And this is necessary for every center.

Answer 1

There are many such centers and these fields are similar everywhere. but the names of the sensors are different.

make id, logentid and name as primary key.

Answer 2

If you have MS SQL Server, then look towards SQL Server Integration Services .
At one time, I used it to collect data from a large number of Access databases into one MS SQL, combing the data along the way, adding the necessary fields and other goodies.