Question

我使用以下sql更新名为userStats的表格，并按照我提供的userId用户运行。

update userStats us
join (select
    sum(postStatus = 0) published,
    sum(postStatus = 1) inactive,
    sum(postStatus = 5) recalled,
    sum(postStatus = 6) deleted
from userData where userId = @x) d on d.userId = us.userId 
set
us.published = coalesce(d.published,0),
us.inactive = coalesce(d.inactive,0),
us.recalled = coalesce(d.recalled,0),
us.deleted = coalesce(d.deleted,0),
us.total = coalesce(d.published+d.inactive+d.recalled+d.deleted,0);

即使列中存在列，我也会遇到错误Unknown column 'd.userId' in 'on clause'。我过去经常使用这个相同的东西而没有错误。

此外，关于where的使用，在设置列之后需要另一个where，或者内部的位置是否足以仅更新userId I供应。它确实只更新userId我提供的内容，但是在那里之后再使用一个where我感到非常不舒服。我是否需要在外面像我之前做过的另一个？

us.deleted = coalesce(d.deleted,0),
us.total = coalesce(d.published+d.inactive+d.recalled+d.deleted,0) where userId =@x;

Answer 1

更改子查询

select
    sum(postStatus = 0) published,
    sum(postStatus = 1) inactive,
    sum(postStatus = 5) recalled,
    sum(postStatus = 6) deleted,userId 
from userData where userId = @x

然后在其工作的where子句中使用userid

Answer 2

表格别名为d，虽然您的userID表格具有值，但未明确选择列userData。

所以，你应该做的事情如下：

(select
    userID,  --> This field has to be selected to use in the join condition
    sum(postStatus = 0) published,
    sum(postStatus = 1) inactive,
    sum(postStatus = 5) recalled,
    sum(postStatus = 6) deleted
from userData where userId = @x) d on d.userId = us.userId 
                                         ^
                                         |___ You were getting error here.

Answer 3

因为您只从内部查询中获取一行，所以您不需要连接条件！

update userStats us
join (select
    sum(postStatus = 0) published,
    sum(postStatus = 1) inactive,
    sum(postStatus = 5) recalled,
    sum(postStatus = 6) deleted
    from userData where userId = @x) d
set
us.published = coalesce(d.published,0),
us.inactive = coalesce(d.inactive,0),
us.recalled = coalesce(d.recalled,0),
us.deleted = coalesce(d.deleted,0),
us.total = coalesce(d.published+d.inactive+d.recalled+d.deleted,0)
where userid = @x

但是你的目标表中确实需要一个where子句。

此查询也可以很好地执行，因为内部和外部查询都使用索引友好的wher子句。

即使列存在，使用更新和连接时的未知列也是如此

3 个答案: