Joining two or more tables at Interface level

Could you provide a bit more detail about the use case? What you're asking is likely possible with some complex manipulations and looping, but creating a view will be much more performant.

I have a requirement to populate a paging grid in a report with data from 2 different CDTs without creating views. I have created 2 expression rules,
Rule1: Fetches data from 1st CDT
Rule2: fetches data from 2nd CDT

There is just 1 field common between both the CDTS.

The total count fetched for the "List of Variants" isn't the same i.e the length differs.

I need help in combining fields from CDT1 and CDT2 in CDT3

I have a requirement to populate a paging grid in a report with data from 2 different CDTs without creating views. I have created 2 expression rules,
Rule1: Fetches data from 1st CDT
Rule2: fetches data from 2nd CDT

There is just 1 field common between both the CDTS.

The total count fetched for the "List of Variants" isn't the same i.e the length differs.

I need help in combining fields from CDT1 and CDT2 in CDT3