SELECT
SUM(quantity) AS qt
FROM
stockMove
WHERE
date_mov >= '2019-04-01'
AND
date_mov <= '2019-04-30'
AND
ProductCode = '000807'
GROUP BY
ProductCode

SELECT COALESCE(SUM(quantity),0) AS qt

SELECT COALESCE(SUM(quantity), 0) AS qt
FROM stockMove
WHERE date_mov >= '2019-04-01' AND date_mov <= '2019-04-30' AND
      ProductCode = '000807';