SELECT不返回我预期的结果

Question

我正在尝试从3个表中选择一组结果。我的目标是从成员表中返回所有成员，并从得分表中返回分数。

$sql = "SELECT member.id, member.firstName, member.lastName, compScore.score1, 
               compScore.score2, compScore.score3, compScore.score4, 
               compScore.score5, compScore.score6, compScore.score7, 
               compScore.score8, compScore.memberId, teamMember.memberId, 
               teamMember.teamId
        FROM member
        JOIN compScore ON member.id = compScore.memberId
        JOIN teamMember ON teamMember.memberId = member.id";

$result = $conn->query($sql);

var_dump($result);
echo $conn->error;

  if ($result->num_rows > 0) {
      while($row = $result->fetch_assoc()) {
          echo $row['firstName'];
          echo $row['score1'];
    }
  }

上述查询仅输出单个结果，而不是成员表中的所有成员。

应该有3个成员输出，但我只得到第一个。

这是我通过var_dump的结果：

object(mysqli_result)#3 (5) { 
    ["current_field"]=> int(0)
    ["field_count"]=> int(14) 
    ["lengths"]=> NULL 
    ["num_rows"]=> int(1) 
    ["type"]=> int(0) 
} jon3

更新

表：

member
id, firstName, lastName

team
id, name

teamMember
id, memberId, teamId

compScore
score1, score2, score3, score4, score5, score6, score7, score8, memberId