Can I install SQL Server on an external Hard Disk? [closed]
Aside from this question being OT in the first place, there is no reason at all to not install SQL Server on a SSD drive; but even if there was one, or if you just didn't want to install it on your system drive... installing it on an external disk makes definitely a lot less sense.
That said, you can do that and it will work (as long as you keep the external disk plugged in); but it's just an astonishingly bad setup.