Skip to main content
cancel
Showing results for 
Search instead for 
Did you mean: 

Earn the coveted Fabric Analytics Engineer certification. 100% off your exam for a limited time only!

Reply
ahuhn
Helper I
Helper I

full outer join in dax

I am trying to do a full outer join in DAX (not in PQ)

 

I have two tables, T1 and T2, and am trying to make a merged table, M, as shown below.

Picture1.png

 

I tried combinations of crossjoin and generate, but cannot find an appropriate solution. Is this possible?

 

Any suggestions welcome

6 REPLIES 6
petrovnikitamai
Resolver V
Resolver V

Very odd error:

 

No common join columns detected. The join function 'NATURALLEFTOUTERJOIN' requires at-least one common join column.

new table = 
naturalleftouterjoin(
selectcolumns(T1;"name";[name];"statusBefore";[statusBefore]);
selectcolumns(T2;"name";[name];"statusToday";[statusToday]))

i'm not sure, but try this

Thanks for the suggestion.

 

I renamed name to name1, made a relationship between the two tables, and ran

 

Table = NATURALLEFTOUTERJOIN('Now','Before')

 

succssfully

Anonymous
Not applicable

@ahuhn  but naturaleftouterjoin function gives only left join results right?  if we need full outer join, is there any function?

I was not able to find a function, but found an approach - 

Full outer join  = Left Join + Right Anti Join.

 

For example - 

I have two tables -

1.PNG

2.PNG

and this is the output required.

3.PNG

This can be achieved by - 

FullOuterJoin = UNION(

    var DepartmentLeftOuterJoinEmp = NATURALLEFTOUTERJOIN(Department,RELATEDTABLE(Emp))
    return SELECTCOLUMNS(DepartmentLeftOuterJoinEmp,
        "DepID", Department[DepID],
        "EmpID", [Emp Id],
        "Income", [Income],
        "Name",[Name],
        "DepName",[Dep Name]
    ),

    var DepartmentUniqueIds = DISTINCT(Department[DepID])
    return SELECTCOLUMNS(CALCULATETABLE(Emp, NOT(Emp[DepID] in DepartmentUniqueIds)),
        "DepID", [DepID],
        "EmpID", [Emp Id],
        "Income", [Income],
        "Name",[Name],
        "DepName"," "
        )
)

the first table is left outer join and the other one is the right anti join, ie. those which is only present in the right table.

Helpful resources

Announcements
April AMA free

Microsoft Fabric AMA Livestream

Join us Tuesday, April 09, 9:00 – 10:00 AM PST for a live, expert-led Q&A session on all things Microsoft Fabric!

March Fabric Community Update

Fabric Community Update - March 2024

Find out what's new and trending in the Fabric Community.