Question

Does anyone know a simple way of copying multiple table rows and it’s related items?

In my simplified example I have two tables, one with a table for companies and one for their employees and I’d like to be able to clone entire companies with all their employees in a simple way.

[Companies]

- ID (Auto-increment)
- Name

[Employees]

- ID
- CompanyID (Foreign Key)
- Name

I’ve been playing around with the OUTPUT-clause but just managed to return the inserted IDs without a reference to the original row.

I just can’t figure out how to link a inserted row to the original one?

If the insert-statement returned a table like this:

@mappingTable

-InsertedCompanyID
-OriginalCompanyID

I could run a statement like this to copy all employees:

INSERT INTO Employees (CompanyID, Name)
SELECT m.InsertedCompanyID, x.Name FROM @mappingTable m 
INNER JOIN Employees x (x.CompanyID = m.OriginalCompanyID)

Or am I on the wrong path? Is there’s a better way to accomplish this?

Answer 1

You can use the output clause of the merge statment to map between the old ID and the new auto incremented ID.

Have a look at this question: Using merge..output to get mapping between source.id and target.id