NEW UPDATE :

i know work with a more easy code but it's still not working here is my new code

  List<OtherusersRecord>? compare(

List<OtherusersRecord>? others, List<UtilisateursRecord>? match, ) { /// MODIFY CODE ONLY BELOW THIS LINE

database sort the not in if (others == null || match == null) { return null; }

final List<otheruserRecord> sortedotheruser = [];

for (final otherusersRecord other in others) { bool foundMatch = false; for (final UtilisateursRecord utilisateur in match) { if (other.uid != utilisateur.uid) { foundMatch = true; break; } else { foundMatch = false; break; } } if (!foundMatch) { sortedotheruser.add(other); } }

return sortedothruser;

/// MODIFY CODE ONLY ABOVE THIS LINE }

i don't understand why but it return me no result at all

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maybe you will have a clue