text: SELECT ISNULL(SUM(p.Price * op.Quantity), 0) AS [Parts Total] 
    FROM Parts AS p
  JOIN OrderParts AS op ON op.PartId = p.PartId
  JOIN Orders AS o ON o.OrderId = op.OrderId
  WHERE DATEDIFF(WEEK, o.IssueDate, '2017/04/24') <= 3 
  