First Occurrence of a Value

[djdubbert]

I want to create a new column with a 1 when the 1st occurence of the 'Occurrences UID' column happens, and the new column to have a 0 for all other instances. In excel the formula is: =IF(COUNTIF($AO$2:AO2,AO2)>1,0,1). How could I accomplish this in Power BI? 

[djdubbert]

This worked! Thank you for your help!

[PaulOlding · Accepted solution]

How do you decide which is the first?  ie how is the list sorted?

In this example I'm sorting by a column called amt.  You can change that for however you want to sort it.  RANKX also has extra parameters for ordering ascending or descending if you need it.

First =

VAR _Current = 'Table'[Occurences UID]

VAR _Rank =

RANKX(

FILTER('Table',

'Table'[Occurences UID] = _Current

),

'Table'[amt]

)

VAR _Result = IF(_Rank = 1, 1, 0)

RETURN

_Result