In some cases, for example when analyzing or optimizing the distribution of Site Collections in a SharePoint farm, it may be helpful to see which Site Collections are stored in which Content Databases. This can easily achieved by using this SharePoint Management Shell cmdlet:

Get-SPSite -Limit All | Select Url,ContentDatabase | Format-Table -Wrap -AutoSize > D:\Output\ShowAllSCs.txt

Alternatively it may also be helpful to dispaly all Site Collections in a certain Content Database:
Get-SPSite -Limit All -ContentDatabase | Format-Table -Wrap -AutoSize > D:\Output\ShowSCsInContentDB.txt

Or display all Site Collections in a certain Web Application:
Get-SPWebApplication https://webapplication.domain.com | Get-SPSite -Limit All | Select Url,ContentDatabase | Format-Table -Wrap -AutoSize > D:\Output\ShowAllSCsInWA.txt