NATURALLEFTOUTERJOIN Performs an inner join of a table with another table. The tables are joined on common columns (by name) in the two tables. If the two tables have no common column names, an error is returned.
Syntax
NATURALLEFTOUTERJOIN(leftJoinTable, rightJoinTable)
Parameters
LeftJoinTable – A table expression defining the table on the left side of the join.
RightJoinTable – A table expression defining the table on the right side of the join.
Return Value
A table which includes only rows from rightJoinTable for which the values in the common columns specified are also present in leftJoinTable. The table returned will have the common columns from the left table and the other columns from both the tables.
Reference Data
https://docs.microsoft.com/en-us/dax/dax-function-reference