DAX Calculate, Sum, Datesbetween duplicate date error

Hi DataScope 

if you already have a specific date period, there is no need to use 'Date Table'. In this scenario, you can use the second measure, it calculates total by filter 'sales_order_item' in a period 

Promo Sales 1 = CALCULATE(SUM(sales_order_item[sale_pricel]), filter('sales_order_item', 'sales_order_item'[order_date]>= DATE(2021,01,01) && 'sales_order_item'[order_date]<= DATE(2021,01,31)))

Here's a post for your reference on when to use a calendar table, 

https://community.powerbi.com/t5/Desktop/Calendar-Table/m-p/1281928

Best Regards,

Community Support Team _Tang

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