When you use .contains(), the search/matching is case insensitive and doesn’t have to be exact. If ‘iMail’ = ‘candidat’, then it will match all your records. Use console.log( $w ( ‘#inputMail’ ). value ) when setting up the filter, to see what the filter is being set to. If you use .eq() then the search IS case sensitive and must match exactly. I suspect the search query is being setup with something other than ‘Candidat1’, which is why you are getting zero, or nothing returned when using .eq().
Because you are setting up your filter to sum for 1 candidate only and you want the total of all vues, your wixData.aggregate function does not need the .group(‘candidat’) line.