My dataset contains Null/Blank values which prevents Select-all by default in my parameter for Customer.
Below mentioned is the DAX query in which I want to remove all the nulls/blanks, so, that it selects all by default in my Customer parameter.

EVALUATE SELECTCOLUMNS (ADDCOLUMNS (SUMMARIZECOLUMNS (ROLLUPADDISSUBTOTAL (‘DIM_Customer'[Customer], “h0”), RSCustomDaxFilter(@SalesSwitchValue,EqualToCondition,[Sales Switch].[Value],String), RSCustomDaxFilter(@DIMCustomerBusArea,EqualToCondition,[DIM_Customer].[Bus Area],String), RSCustomDaxFilter(@DIMCustomerCustomerGroup,EqualToCondition,[DIM_Customer].[Customer Group],String), RSCustomDaxFilter(@DIMCustomerCustomerSubGroup,EqualToCondition,[DIM_Customer].[Customer Sub Group],String)), “ParameterLevel”, if ([h0], 0, 1)), “ParameterCaption”, SWITCH([ParameterLevel], 1, ‘DIM_Customer'[Customer], “Blank()”), “ParameterValue”, ‘DIM_Customer'[Customer], “ParameterLevel”, [ParameterLevel], “‘DIM_Customer'[Customer]”, ‘DIM_Customer'[Customer]) order by ‘DIM_Customer'[Customer], [ParameterLevel]

Where NOT ISBLANK() should be applied in this DAX query or any other filter to remove the unwanted Null/Blank values.

I’ve tried applying the filters but my query throws an error called “Query Preparation Failed”, wrong placement of filters ig.