無法讓我的 JOIN 適合此查詢

使用http://sqlfiddle.com/#!18/fce3e/1上的 SQL Fiddle ，我試圖得到以下結果，但無法理解它。我不想指定特定的類別或 personId 值。

謝謝你。

| id | message | category | personId | enabled |
|----|---------|----------|----------|---------|
|  1 |   Hello |        1 |        1 |       1 |
|  2 |      Hi |        1 |        1 |       1 |
|  3 |     Hey |        1 |        1 |       0 |
|  4 |    Argh |        2 |        1 |       0 |
|  5 |     Yar |        2 |        1 |       0 |
|  6 |  Hooray |        2 |        1 |       0 |
|  1 |   Hello |        1 |        2 |       0 |
|  2 |      Hi |        1 |        2 |       0 |
|  3 |     Hey |        1 |        2 |       0 |
|  4 |    Argh |        2 |        2 |       1 |
|  5 |     Yar |        2 |        2 |       1 |
|  6 |  Hooray |        2 |        2 |       0 |
|  1 |   Hello |        1 |        3 |       0 |
|  2 |      Hi |        1 |        3 |       0 |
|  3 |     Hey |        1 |        3 |       1 |
|  4 |    Argh |        2 |        3 |       0 |
|  5 |     Yar |        2 |        3 |       0 |
|  6 |  Hooray |        2 |        3 |       0 |

SELECT message.Id, 
      message.message,
      message.category,
      person.Id personId, 
      CASE WHEN personmessage.messageId IS NULL 
           THEN 0 
           ELSE 1
           END enabled 
FROM message
CROSS JOIN person
LEFT JOIN personmessage ON personmessage.personId = person.Id
                      AND personmessage.messageId = message.Id
ORDER BY 4,1

小提琴

引用自：https://dba.stackexchange.com/questions/256249