Is there a way to compare timestamps with different formats?

I am trying to compare the response from database and web services.

response from web services is : 2020-01-07T17:15:00-08:00
response from database is :     2020-01-08 01:15:00.0

How to convert both of them to a common format?

Or

Is there a way to use substring to match an compare?

Please help. Have been stuck on this for three days.