New table with distinct values from several tables

Hello, 

I have several tables with same field in each

Table 1

- Region

- Segment

- #Visits

Table 2

- Region 

- Code

- #Cost

Table 3

- Region

- Vertical

- #price

I wanted to create a fourth table with the distinct value of "region" field from my 3 tables to be able to use as a filter.

Thanks for help