Retrieving this information without a rescan will not be possible unfortunately. If the information isn't listed on this page it means it's not in your Lansweeper database.
A rescan resolving the issue proves that it is retrievable though. It may be that your assets were initially scanned with a freeware license active (which disables the retrieving of SQL Server Information) or that you had the "SQLServer" item disabled under Scanning\Scanned Item Interval. The "SQLServer" item has an interval of 3 days, meaning your regular scans should be picking it up every 3 days (a rescan ignores this interval). For more information on scanned item intervals you can check out
this article.