code correction pls help

pls help me to correct the code

[Field : Vch LastPurRate]
Use : Rate Price Field
set as : If $$IsEmpty$LastPurcCost:StockItem:$Stockitemname) then then $$NUmber:0 else $StandardPrice:StockItem:$Stockitemname
Storage : StkLastPurRate

i am trying to do, if my standard selling price not mentioned then it should take my last purchase cost

 

Try this
$(Stockitem,$Stockitemname).StandardpriceList[1].Rate

 

Thank you sir.. for your reply

if am using this code

set as : $(Stockitem,$Stockitemname).StandardpriceList[-1].Rate

then its taking last std selling price but not taking effecting date,
example : if i mention std selling price 350 effecting date next month 1-4-22 but it takes for current date also


and if i use this code


set as : $(Stockitem,$Stockitemname).StandardpriceList[1].Rate
then it takes first entered price ...