显示重复行的MySQL

我有两个表，

人

和

评论

Table: people
+-------------------+----------------+-------------+------+
| id |      cn      |       en       |     dob     | role |
+-------------------+----------------+-------------+------+
| 1  |  ChineseName |   EnglishName  |  1989-03-02 |   0  |
+-------------------+----------------+-------------+------+
| 2  | ChineseName2 |   EnglishName2 |  1923-06-12 |   1  |
+-------------------+----------------+-------------+------+

Table: comment
+----+--------+----------+-------------------+---------------------+
| id |  owner | owner_id | creator_person_id |       comment       |
+----+--------+----------+-------------------+---------------------+
| 1  | PERSON |     2    |          1        |  Some comments here |
+----+--------+----------+-------------------+---------------------+
| 2  | TRANSAC|     1    |          1        |       Comments      |
+----+--------+----------+-------------------+---------------------+
| 3  | PERSON |     1    |          1        |     Comments here   |
+----+--------+----------+-------------------+---------------------+

执行查询时：

SELECT comments.comment, 
creator_person.id AS creator_id,
creator_person.cn AS creator_cn,
creator_person.en AS creator_en,
creator_person.dob AS creator_dob,
creator_person.role AS creator_role
FROM people, comments
JOIN people AS creator_person
ON comments.creator_person_id = creator_person.id AND comments.owner = 'PERSON' AND comments.owner_id = 1
ORDER BY people.id

我想它只会返回1行，但是我得到了该行的一个副本：

+------------------+------------+-------------+-------------+-------------+--------------+
|      comment     | creator_id | creator_cn  | creator_en  | creator_dob | creator_role |
+------------------+------------+-------------+-------------+-------------+--------------+
|   Comments here  |      1     | ChineseName | EnglishName |  1989-03-02 |       0      |
+------------------+------------+-------------+-------------+-------------+--------------+
|   Comments here  |      1     | ChineseName | EnglishName |  1989-03-02 |       0      |
+------------------+------------+-------------+-------------+-------------+--------------+

您应该更改：

FROM people, comments

致：

由于您加入的是

people

表，因此不需要将其包含在

FROM

子句中

您还需要更新order子句以反映您在people表中提供的别名：

ORDER BY creator_person.id

---

您可以加入

人员

表两次。因此，您可以将查询修改为：

SELECT comments.comment, 
creator_person.id AS creator_id,
creator_person.cn AS creator_cn,
creator_person.en AS creator_en,
creator_person.dob AS creator_dob,
creator_person.role AS creator_role
FROM comments
INNER JOIN people AS creator_person
ON comments.creator_person_id = creator_person.id 
   AND comments.owner = 'PERSON' AND comments.owner_id = 1
ORDER BY creator_person.id

如果出现相同的问题，也可以添加

distinct

关键字，如：

SELECT distinct comments.comment, ...
...
...

---

你在那里有一个额外的连接（在

人物，评论
中有一个隐式连接，因为你在与人进行内部连接之后，应该首先删除该连接）


我还将其他验证从on子句移动到where子句。在这种情况下，您正在进行内部联接，这不会有什么区别，但这是一个坏习惯，可能会使您在将来使用左/右联接时做一些奇怪的事情
谢谢您的快速回复，然而，它在“order子句”中的
#1054-未知列“people.id”上给了我错误
我应该如何解决这个问题？然后将其更改为
order BY creator_person.id
。另外，我已经修改了答案谢谢你的快速回复，但是它在“订单条款”中的
#1054-未知列“people.id”上给了我错误。
我应该如何解决这个问题？
SELECT distinct comments.comment, ...
...
...

select comments.comment,
  creator_person.id as creator_id,
  creator_person.cn as creator_cn,
  creator_person.en as creator_en,
  creator_person.dob as creator_dob,
  creator_person.role as creator_role
from comments
inner join people as creator_person
  on comments.creator_person_id = creator_person.id
where comments.owner = 'PERSON' and comments.owner_id = 1
order by creator_person.id;