Get the last average monthly price of each product

I want to obtain from each product the average price of the last month that each product was sold. A problem is generated in the second temporary table "price_avg" because when you change the calculation from avg (punitdolar) to price_ultimoUSD (sum (i.quantity * i.punitdolar) / sum (i.quantity)) as price_ultimateUSD to execute the query I get

  

"Msg 8134, Level 16, State 1, Line 64 Divide by zero error   encountered. "

Try to fix it with a quantity > 0 so that it does not take negative amounts or 0 but the issue is that in doing so it stops recognizing last date and averages all the products with the same code.

Possible solution in this:

(sum(i.cantidad*i.punitdolar)/sum(i.cantidad)) as precio_ultimoUSD 

go some kind of conditional that says that if the amount that divides is zero put 0 and no error

with fecha_ultima as (select itemnumber,
    max(format(fecha, 'yyyyMM')) as Fecha_ultim from [gpper].[dbo].[peru_sales_report]
group by itemnumber)                                                        
--Vinculo de ultima fecha y precio promedio
,precio_avg as ( 
select u.itemnumber,
    u.fecha_ultim,
    (sum(i.cantidad*i.punitdolar)/sum(i.cantidad)) as precio_ultimoUSD
    --avg(punitdolar) as precio_ultimoUSD                                
from [gpper].[dbo].[peru_sales_report] i 
    left join fecha_ultima u  
    on i.itemnumber = u.itemnumber and format(i.fecha, 'yyyyMM') = u.fecha_ultim where i.cantidad <> 0
group by u.itemnumber, u.fecha_ultim) --Join con tabla precios
,precioabc as (
select a.*,
    b.precio_ultimoUSD from [dbo].[Precio_Inyeccion_soplado] a 
    left join precio_avg b
    on (a.id_producto = b.itemnumber)) --Join final con v_producción_altas
select a.*,
    a.peso_real_op/1000 as toneladas,
    c.virgen_rec,
    b.pesokilos as peso_unitario, 
    c.precio_teoricoUSD,
    f.precio_ultimoUSD,
    (costo_kardex/cantidad/3.24) as costo_unitarioUSD, 
    f.precio_ultimoUSD*a.cantidad as ingresoUSD,
    f.precio_ultimoUSD*a.cantidad-costo_kardex/3.24 as margenUSD from [GESTION].[prod].[v_produccion_altas] a 
    left join [gpper].[dbo].[Peru_Maestro_Articulos] b
    on (a.id_producto = b.Codigo)
    left join  [dbo].[Precio_Inyeccion_soplado] c
    on (a.id_producto = c.id_producto)
    left join  precioabc f
    on (a.id_producto = f.id_producto) where a.linea_negocio <> 'extrusion' and a.linea_negocio <> 'reventa'