How to implement FULL JOIN on Redash 6.0.0+b8536

So I have an query resluts thats join 3 table but one of table do not match, but i want to show their table results, how can i do that? my case is, i want to show total count every table by their created month

example:
Current results like this
month, table 1, table 2, table 3
Jan,10,10,1
Mar,11,112,2

But i want to show results like this
month, table 1, table 2, table 3
Jan,10,10,1
Feb,12,2,0 ( This is not show on the first example, because on table 3 data with month Feb doesn’t exists. **notes: i do join by their month )
Mar,11,112,2