SQL JOIN获得不正确的值

Question

我有这个代码

Select  proinfo.ProjectN AS 'BS',
        proinfo.Weight AS 'Poids Dossier Kg',

        Cast((SUM(Case when  DailyFab.FK_idNextProcess=13 
        then ProjShFab.[Weight] * DailyFab.[Quantity] Else 0 End)/proinfo.Weight)*100 as decimal(10,2)) as 'Taux Fab',

        Cast((SUM(Case when  DailyShipp.FK_idNextProcess=14 
        then ProjShFab.[Weight] * DailyShipp.[Quantity] Else 0 End)/proinfo.Weight)*100 as decimal(10,2)) as 'Taux Exp'

FROM 
    [dbo].[ProjectShipping] ProjShFab
    Inner JOIN ProjectInfo proinfo ON proinfo.id = ProjShFab.IdProject 
    Left Join DailyShippingSteelNavision DailyShipp on DailyShipp.FK_idPartShip= ProjShFab.id
    Left Join DailyPaintProduction DailyFab on DailyFab.FK_idPartShip= ProjShFab.id

    Group By proinfo.ProjectN,proinfo.Weight
    Order by proinfo.ProjectN 

当我运行它时，我在“ Taux Fab”和“ Taux Exp”中都得到了不正确的值，但是假设我注释了这行代码

--Left Join DailyPaintProduction DailyFab on DailyFab.FK_idPartShip= ProjShFab.id

然后我运行代码，在“ Taux Exp”中获得正确的值，反之亦然 我为什么会有这个问题，以及如何解决这个问题，请先谢谢。