Keep getting error when trying to use =related function in PowerPivot

Question

Greetings,
I have created a relationship between two tables based on a common field in PowerPivot, and whenever I use the =related() function to try and bring data from a field in one table to a field in another table, I keep getting and error message that says:
The column 'XXXX[xxxx]' either doesn't exist or doesn't have a relationship to any table available in the current context.
Any ideas? I've made this work before in a different dataset so I'm not sure what I'm missing. I have a feeling it might be really basic, but I'm spinning my wheels here.
Thanks very much!
MFW

Answer 1

Hi MFW,
This sounds like the table where you are trying to use the RELATED function from is on the
one side of the one-to-many relationship (i.e. the relationship arrow is pointed towards it). If in reality there is only a
one-to-one relationship between the data and you only need to bring the data from one table to the over, you can simply reverse the direction of the relationship and the RELATED function will work as expected. If this is not the case then you'll
need to use RELATEDTABLE instead of RELATED and some kind of aggregation or computation that ensures that a single value is returned  for the column you are trying to get data from. There is also another function called CALCULATE which can be used for
this scenario.
Imagine that we have two simple tables: Table1 and Table2...
Table1
Column1
Column2
1
A
2
B
Table2
Column1
Column2
1
AA
2
BB
...and create a relationship where Table1 is on the many side and Table2 is on the one side i.e. Table1 -> Table2
We could use a number of methods to pull the the values from Column2 in Table1 into a new Calculated Column in Table2.
If the column we are trying to pull contains text values then we could use a combination of the CALCULATE and LASTNONBLANK function:
=CALCULATE(LASTNONBLANK(Table1[Column2], TRUE()))
If the Table1[Column2] contained only numeric or date values then we could use a combination of the RELATEDTABLE and MAXX functions:
=
MAXX(
RELATEDTABLE(Table1),
Table1[Column2]
An alternative to the DAX directly above is to use the CALCULATE and MAX functions:
CALCULATE(MAX(Table1[Column2]))
You can learn more about the functions I have referred to below:
CALCULATE
LASTNONBLANK
RELATEDTABLE
MAXX
Regards,
Michael Amadi
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