If you are not having the database files (mdf and ldf) files, you can download the stack overflow demo database files.

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Method 1: Using SSMS UI

  1. Open object explorer in SSMS and connect to the server.
  2. Right click on the Databases folder and select Attach.
1113_20220405_102326.png
  1. Click Add and select the mdf file and verify the database name and file locations.
1114_20220405_102710.png
  1. Click Ok to create the database.
1116_20220405_104147.png

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Method 2: Using T-SQL query

-- change the file location accordingly
USE [master]
GO
CREATE DATABASE [StackOverflow2010] ON 
( FILENAME = N'C:\Program Files\Microsoft SQL Server\MSSQL15.SQLSERVER2019\MSSQL\DATA\StackOverflow2010.mdf' ),
( FILENAME = N'C:\Program Files\Microsoft SQL Server\MSSQL15.SQLSERVER2019\MSSQL\DATA\StackOverflow2010_log.ldf' )
 FOR ATTACH
GO
If this query has helped you to solve an issue, you may also like the other T-SQL queries I have posted at blog.rajanand.org