Query migration

Hi, experts.

I'd like to ask about query migration.(3.x & 7.x)

1.Is there any way to know which query is not migrated?

Is there any function?

2.The statistic function of 3.x and 7.x(after migrated) is the same?

display, extract,etc

3.needs some advice if 3.x and 7.x are intermingled.

Thanks and best regards,

Keiko