Power BI Paginated Report parameters with (Null) values

So if you want to handle the scenario where they either pick on currency or by default if the parameter is null they get all of them then you could use the COALESCE function. What coalesce does is to return the first non-null value, so if the parameter is null it will return the value of the parameter itself

EVALUATE SUMMARIZECOLUMNS

(

'ART REP048 UKGAAP'[Accounting_Date],

 'ART REP048 UKGAAP'[Entered_Currency],

 'ART REP048 UKGAAP'[Accounting_Period],

FILTER(VALUES('ART REP048 UKGAAP'[Entered_Currency]), ('ART REP048 UKGAAP'[Entered_Currency] = COALESCE( @EnteredCurrency, 'ART REP048 UKGAAP'[Entered_Currency] )))

)

A similar alternative if you want to use a dropdown list in your parameter is to union on a value like "<ALL>" in the query for you parameter values then use an IF to check for this.

FILTER(VALUES('ART REP048 UKGAAP'[Entered_Currency]), ('ART REP048 UKGAAP'[Entered_Currency] = IF( @EnteredCurrency = "<ALL>", 'ART REP048 UKGAAP'[Entered_Currency], @EnteredCurrency )