Mysql SQL使用2个左联接返回不正确的数据

我已经编写了一个MYSQL脚本，它返回不正确的数据。我精通SQL，但此查询没有返回正确的结果。有人能看看发生了什么事吗。问题是没有时间，没有时间。这两列的值相同，并且也是大值

    select
           a.user_name as userName,
           coalesce(count(b.sp_user_name),0) as noOfBids,
           coalesce(ROUND(AVG(b.a_amount),2),0) as avgAmount,
           coalesce(count(d.sp_user_name),0) as noOfRatedTimes,
           coalesce(ROUND(AVG(d.user_rate),2),0)
    from users a
    left join project_imds b
       on b.sp_user_name = a.user_name
    left join projects c
       on b.project_code = c.project_code
    left join sp_user_rating d
       on d.sp_user_name = b.sp_user_name
    where a.user_type = 'SP'
    and a.active = 'Y'
    group by a.user_name
    order by coalesce(ROUND(AVG(d.user_rate),2),0) desc;

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我已经创建了一个解决方法，通过创建一个临时表来获取平均值，并将其连接到主查询

由于我不知道您查询背后的具体数据，这只是一个猜测。但也许你更愿意将“sp_用户_评级”直接加入到“用户”中，改变

select
       a.user_name as userName,
       coalesce(count(b.sp_user_name),0) as noOfBids,
       coalesce(ROUND(AVG(b.a_amount),2),0) as avgAmount,
       coalesce(count(d.sp_user_name),0) as noOfRatedTimes,
       coalesce(ROUND(AVG(d.user_rate),2),0)
from users as a
left join project_imds as b
   on b.sp_user_name = a.user_name
left join projects as c
   on b.project_code = c.project_code
left join sp_user_rating as d
   on d.sp_user_name = b.sp_user_name
where a.user_type = 'SP'
and a.active = 'Y'
group by a.user_name
order by coalesce(ROUND(AVG(d.user_rate),2),0) desc;

left join sp_user_rating d
   on d.sp_user_name = b.sp_user_name

到

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为什么这不同/帮助？我也看不出原始查询和此查询之间有任何区别？使用AS关键字添加到查询中

left join sp_user_rating d
   on d.sp_user_name = a.user_name