Sharing another interesting interview question in the category of SQL Server Database Backup and Restore.

The question is: Can we restore the only data file (.mdf file) from the backup of SQL Server.
The answer is: Yes, we can restore only .mdf file from the backup of SQL Server (.bak file)

How?

First get the file id from the backup file:
execute below RESTORE and search fileID for the data file (.mdf file)
In my case, fileID =1

RESTORE FILELISTONLY FROM DISK = 'D:\SQL Backup\TestBackup.bak'

Use fileID for restoring only that file data file:

RESTORE DATABASE TestBackupFROM DISK = 'D:\SQL Backup\TestBackup.bak'
WITH
       FILE = 1,
       RECOVERY

Now, ready for Next Question:

Question is: Can I bring the database into the ONLINE state without database log files?
Answer is: No, not possible

If you notice the above RESTORE DATABASE, I wrote RECOVERY which will force SQL Server to rebuild the transaction log and will bring the database in ONLINE state.

All the best!