SQL Create Multiple Column from Multiple Tables

Question

SQL SERVER 2017

Some help

Error is line 4

 

I need first column Naziv artikla  (Line 1)

second column Prodata Kolicina (Line 2)

Third column Nabaljena kolicina (Line 4)  some error

Fourth column difference Line4 - Line 2 as Ukupno

SELECT  roba as 'Naziv artikla',
SUM (cast(kolicina as float)) as 'Prodata kolicina'
from (select roba, kolicina from mp_racun_roba union all select roba, kolicina from mp_faktura_roba) as alltables
INNER JOIN mp_ulazni_racun_ostalo_roba ON alltables.kolicina=mp_ulazni_racun_ostalo_roba.kolicina as 'Nabavljena kolicina'
--SUM COLUMN 'Nabavljena kolicina' - 'Prodata kolicina'  //result column
group by roba