Bonjour,
solution via une macro, lancer la macro via ALT-F8
Sub aargh()
Set pl = ActiveSheet.UsedRange
Set re = pl.Find("NULL", lookat:=xlPart, LookIn:=xlValues)
If Not re Is Nothing Then
fa = re.Address
fini = False
Do
If re.Offset(1) <> "" And InStr(re.Offset(1).Value, "NULL") = 0 Then re.Value = re.Offset(1).Value Else re.Value = re.Offset(-1).Value
Set re = pl.FindNext(re)
If re Is Nothing Then
fini = True
ElseIf re.Address = fa Then
fini = True
End If
Loop Until fini
End If
End Sub