SQL - Sumas Mysql

SELECT  SUM(detalle_factura.cant_prod)AS cantProd

FROM detalle_factura , factura , `asignfac`

WHERE detalle_factura.`id_prod`=`detalle_factura`.`id_prod`

AND `detalle_factura`.`id_fac` BETWEEN 7 AND 8

AND `asignfac`.`id_cajero`='1104592157'

AND `detalle_factura`.`id_fac`=`asignfac`.`id_fac`

GROUP BY `id_prod`

SELECT df.id_prod as Producto

,sum(df.cant_prod) as Cantidad

FROM asignfac af

inner join factura fa on af.id_cajero = fa.id_cliente

inner join detalle_factura df on df.id_fac = fa.id_fac

where df.id_prod between 7 and 8

and af.id_cajero = '1104592157'

group by df.id_prod

select  df.id_prod as id_prod, sum(df.cant_prod) as cantidad, SUM(df.ptotal_prod) AS totdetalle,

from detalle_factura df

inner join asignfac af on df.id_fac=af.id_fac

where df.id_fac between 12 and 15

and af.id_cajero='1104592157'

group by df.id_prod