Hi Philippe, Your second query appears to be correct. Is it possible that one of the "expropriation" records is suppressed in the the OPAC? Try searching for "title:expropriation AND suppress:true" (without QueryAutoTruncate). It's possible to automatically add parentheses to both the query and the limits by editing the Koha/SearchEngine/Elasticsearch/QueryBuilder.pm file. After "$search_param_query_str = join( ' ', $self->_create_query_string(@search_params) );" add: if ($search_param_query_str) { $search_param_query_str = "($search_param_query_str)"; } my $search_param_limits_str = $self->_join_queries( $self->_convert_index_strings(@$limits) ); if ($search_param_limits_str) { $search_param_limits_str = "($search_param_limits_str)"; } And then change the "$query_str" to: $query_str = join( ' AND ', $search_param_query_str || (), $search_param_limits_str || () ); Hopefully that will produce the correct results. Regards, Kevin