How to sum employee paychecks from multiple jobs into one table - sql

Question

table featuring fictitious employee data, area ( in hectares (ha)) cleared (noted in french as superficie), rate for 1 hectare of cleared land on the specific lot (french:taux) and amount due( expr1) for that lot.
My problem here is that I want the total amount due for each Worker, not the amount due for each worker for each lot. Totals for Sirs Alain, Jacques, Paul, Roger and Tanguay should normally be 4066, 4082 , 5638, 5811 and 3131 , respectively.
My code so far is this
SELECT tbl_Employés.Num_deb, tbl_Employés.Prénom, tbl_Employés.Nom, tbl_Employés.Age, tbl_Employés.DEP, tbl_Employés.Expérience, tbl_Employés.Adresse, Tbl_terrain.superficie, Tbl_terrain.Taux, [superficie]*[taux] AS [Montant à payer]
FROM tbl_Employés INNER JOIN Tbl_terrain ON tbl_Employés.Num_deb = Tbl_terrain.Num_deb
ORDER BY tbl_Employés.Nom;
I have so far tried to use GROUP BY Numéro_terrain, which returns an error that my query does not include the specified expression ''Num_deb'' as a part of an aggregation fuction
I woul greatly appreciate any imput. I am very sorry if you have a hard time understanding some words, as I am doing my best to translate everything from french.

Answer 1

One method is to include all the columns in the GROUP BY that are not arguments to aggregation functions:
SELECT e.Num_deb, e.Prénom, e.Nom, e.Age, e.DEP, e.Expérience, e.Adresse,
SUM([superficie]*[taux]) AS [Montant à payer]
FROM tbl_Employés as e INNER JOIN
Tbl_terrain as t
ON e.Num_deb = t.Num_deb
GROUP BY e.Num_deb, e.Prénom, e.Nom, e.Age, e.DEP, e.Expérience, e.Adresse
ORDER BY e.Nom;