Seconds to understand SQL intersect

First we introduce the word intersect, we put inter and sect separate query, to understand. Inter: In the middle (internet,net is the net, the Internet represents communication within the network). and sect the meaning of the circle, denomination. Intersect said that in the circle of communication, the content of communication must be shared between the exchange of things.

So intersect means the intersection.

1 Select  from T_industriesm 2 intersect 3 Select  from T_industries

What to say:

1 Select  from (Selectdistinctfrominnerjoin2 (select  Distinctfrom on   a.f_name=b.f_name

The two codes are equal:

Seconds to understand SQL intersect