How would I created this sort using LLBLgen

ORDER BY COALESCE(DeliveryDate,ReturnDate) DESC

Self Serving .net 2.0

COALESCE is a database function.

So you can use LLBLGen Pro DBFunction calls to retunr the appropriate Expression which can be set to the Field passed to the Sort Expression.

ref: LLBLGen Pro's Manual "Using the generated code -> Calling a database function"

I tried this but it doesn't compile

dsOTS.SorterToUse = New SortExpression(New DbFunctionCall("COALESCE", New Object() {OrderTrackingViewFields.DeliveryDate,  OrderTrackingViewFields.ReturnDate}) Or SortOperator.Descending)

Any suggestions?

The new sort expression expects an EntityField. would you please try the following?

EntityField myField = OrderTrackingViewFields.DeliveryDate //any field will do.
myField.ExpressionToApply = New DbFunctionCall("COALESCE", New Object() {OrderTrackingViewFields.DeliveryDate, OrderTrackingViewFields.ReturnDate})
dsOTS.SorterToUse = New SortExpression(myField Or SortOperator.Descending)