expression is right ?

[Anonymous]

(Sum (if("Date d'entrée") < ('31/01')  and GetFieldSelections(year))

and

(Sum ( if ([Date de sortie]) => ('01/01') and GetFieldSelections(year))))

[jwjackso]

If these are date fields,

=Sum({<[Date d'entrée]={"<$(=MakeDate(GetFieldSelections(year),01,31))"},[Date de sortie]={">=$(=MakeDate(GetFieldSelections(year),01,31))"}>} SomeAmt)