在mysql查询中无法避免重复的结果

Question

我已经使用了stackoverflow上提出的所有解决方案来解决我的问题，但它仍未解决：

我需要获得由plan_id订购的出价用户而不会重复。这是我使用的查询：

    SELECT DISTINCT b.*, u.username, u.name, s.plan_id, s.user_id FROM #__jb_bid b

    "INNER JOIN #__users u ON b.user_id=u.id ".
    "INNER JOIN #__jb_plan_subscr s ON b.user_id=s.user_id ".
    "WHERE b.project_id =".$id."".
    "ORDER BY s.plan_id";

我正在使用Joomla 3和个性化组件，我有这样的结构：

__ jb_bid表：

------------------------------------
|id | user_id | project_id |
|-----------------------------------
|1  | 22      |     1      |
|2  | 24      |     1      |
|3  | 23      |     1      |
|4  | 25      |     1      |
|5  | 26      |     2      |
------------------------------------

__ jb_users表：

------------------------------------
|id | username    | name           |
|-----------------------------------
|22  | username22   |     name22      |
|23  | username23   |     name23      |
|24  | username24   |     name24      |
|25  | username25   |     name25      |
|26  | username26   |     name26      |
|27  | username27   |     name27      |
------------------------------------

__ jb_plan_subscr表:( user_id 22有两个计划）

------------------------------------
|id | user_id    | plan_id    |
|-----------------------------------
|1  | 22         |     1      |
|2  | 22         |     2      |
|3  | 23         |     1      |
|4  | 24         |     1      |
|5  | 25         |     1      |
------------------------------------

查询结果为：

username22
username24
username25
username22
username23

由于

Answer 1

<强> SQL Fiddle Demo

SELECT b.*, u.username, u.name, s.plan_id, s.user_id 
FROM (SELECT `user_id`, MAX(`plan_id`) `plan_id`
      FROM __jb_plan_subscr 
      GROUP BY `user_id`
     ) s
INNER JOIN  __jb_bid b
  ON  b.user_id = s.user_id 
INNER JOIN __jb_users u 
  ON b.user_id = u.id
WHERE project_id = 1
ORDER BY s.plan_id;

<强>输出

| id | user_id | project_id |  username |  name | plan_id | user_id |
|----|---------|------------|-----------|-------|---------|---------|
|  2 |      24 |          1 | username3 | name3 |       1 |      24 |
|  1 |      22 |          1 | username1 | name1 |       2 |      22 |