-- Ventas (Facturas menos devoluciones) por cliente en un año
SELECT 
	dv.id_cliente AS Nit,
       	SUM(dvi.valor) AS Net_Sales, 
	ROUND(
		SUM(
			dvi.cantidad * i.peso * (IF(dvi.valor >0, 1 , -1))
		),
		2
	) AS Amount_Kg,
       	SUM(dvi.costo) AS Cost_of_goods_sold,
	c.nombre_cliente AS Cliente

FROM
	documento_ventas dv
	LEFT JOIN cliente c
		USING ( id_cliente )
	JOIN documento_ventas_has_item dvi 
		ON ( dv.id_documento = dvi.id_documento
			AND dv.id_sucursal = dvi.id_sucursal )
	JOIN item i
		USING ( id_item )

WHERE
        (LEFT(dv.id_documento,2) = 'DV' OR
         LEFT(dv.id_documento,2) = 'EF' OR
         LEFT(dv.id_documento,2) = 'EI' OR
         LEFT(dv.id_documento,2) = 'AI' OR
         LEFT(dv.id_documento,2) = 'CF' OR
         LEFT(dv.id_documento,1) = 'F')
	AND YEAR(dv.fecha) = 2019

GROUP BY
	Nit

ORDER BY
	Nit