Subquery in SQL report builder

Hey all, I'm converting BAQ's from Epicor to SSRS reports in Report Builder and ran into a bit of a problem. I have the below code:

select((min(salesrep.repreportsto)))as[Calculated_Region],((min(Customer.Name)))as[Calculated_Name],((min(invchead.invoicedate)))as[Calculated_invoicedate],((sum(invcdtl.extprice)))as[YTD_2018],(SUM(YTD_2018)OVER(PARTITIONby@Begin_DateORDERBYcustomer.Name))as[Calculated_running_total]

When I try to run this, I'm getting "Invalid column name YTD_2018". I'm assuming this is because the query hasn't been ran yet so the alias is not recognized. Either way, would this situation require a subquery/report? If so, anyone have a link for an example setup?

Thanks!