The specified name has the same name as an existing database. Please specify another database name. I hope someone who knows can answer it?

Because the name of the library you want to attach has the same name as the existing library, just change the name.

CREATE DATABASE [rename database name] ON

(FILENAME = N'D:\tmp.mdf'),

(FILENAME = N'D:\tmp_log.ldf')

FOR ATTACH

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In your picture, give it a random name after "Attach as"

Or add it to the existing Right-click on the library -> Rename to rename the original library