I have user, position and unit table.
If I use select distinct, the result does not contain any column of position and unit:

   public function getUsersByType(array $types)
    {
        $query = $this->db->getQueryBuilder();

        $query
        ->selectDistinct("u.*", "position.position_name", "unit.unit_name")
        ->from("qlcb_user", "u")
        ->leftJoin(
            "u",
            "qlcb_unit",
            "unit",
            $query->expr()->eq("u.unit_id", "unit.unit_id")
        )
        ->leftJoin(
            "u",
            "qlcb_position",
            "position",
            $query->expr()->eq("u.position_id", "position.position_id")
        );

        // $this->applyDynamicFilters($query, $types);

        $result = $query->execute();
        return ["users" => $result->fetchAll()];
    }

Without distinct, the code works perfectly. I don’t know why