Course Liam!

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&& Delete the detail.
Delete From ordersdetail Where idorder == orders.idorder

&& Delete the header.
Delete In orders

&& Move to first order and reload the detail.
Go Top In orders
Select idproduct,name,unitcost,quantity,unitcost*quantity as total ;
From ordersdetail Left Outer Join products ;
On products.idproduct == ordersdetail.idproduct ;
Into Cursor curDetail Readwrite ;
Where ordersdetail.idorder==orders.idorder And !Deleted("ordersdetail")
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The result is a "curDetail" empty cursor after de query.