PS C:\> Get-SPContentDatabase -Identity "ContentDB" | Remove-SPContentDatabase Confirm
Are you sure you want to perform this action?
Performing operation "Remove-SPContentDatabase" on Target "ContentDB".
[Y] Yes [A] Yes to All [N] No [L] No to All [S] Suspend [?] Help
(default is "Y"):y Confirm
Removing 'ContentDB' will permananetly delete the SQL database, permananetly
deleting all content stored within it. Use Dismount-SPContentDatabase if you do
not want to delete the SQL database.
[Y] Yes [A] Yes to All [N] No [L] No to All [S] Suspend [?] Help
(default is "Y"):y
PS C:\>