I have difficulties to make a left join with multiple columns as keys. One of the columns can have empty cells (null) and it seems that the join is considering that no value can be found with the join. For example : Key : Columns 1 , 2 and 3.
left table : A B C D D E Null F
on the right table: A B C G D E Null H
result : A B C D G D E Null F Null
So Dataiku seems to not recognize an empty value as a valid key and so it is removing the values.