Getting many-to-many relationship even when one of the column created is using DISTINCT Need 1toMany

[Avinash_Sah]

Their is a table with a column having something like this:

DISTINCT(UNION(ALL('table1'[col_name1]),ALL('table2'[col_name2])))

And I want to create relationship to another table using the same column.
It should be 1-to-many as it is having distinct entries. But instead it is giving many-to-many.
It don't know why it is so.

There is data like: 
1. Dog
2. Dogs
3. Cat
4. Cats

Maybe that "...s" in the end is causing issue. I don't know facing this for the first time.

[jdbuchanan71]

@Avinash_Sah 

I'm wondering if it has something to do with the blank row a model adds to a table for missing relationships.  ALL grabs that row.  Try it like this.

DISTINCT(UNION(DISTINCT('table1'[col_name1]),DISTINCT('table2'[col_name2])))

DISTINCT will not pull the blank row from the source tables.

[Avinash_Sah · Accepted solution]

It was Null values that was causing the issue, removing them from edit query option did the thing. Your solution also looks like it would work.