How to Merge Database

How to merge to database if accidentally install two time.
Now its type condition. If I remove a domain (www.mydomain.in- mydata_wp1) then the other is not running. The entire website disappears. how can it sovle.

now i have two database single domain. as like

https://www.mydomain.in- mydata_wp1

https://www.mydomain.in – mydata_wp2