SQL Server 2016：将 FOR XML 和 STUFF 与多连接查询结合使用

如何解决SQL Server 2016：将 FOR XML 和 STUFF 与多连接查询结合使用

我有一个出于报告目的的查询，以列出未提交季度报告的雇主和未提交季度报告的雇主。这是我的查询：

with employerIds as (select distinct Employerid
                from employerTransaction),quarters as (select distinct QId
                    from employerTransaction)
select ei.EmployerId,e.EmployerName,q.QId
from employerIds as ei
cross join quarters as q
left join employerTransaction as et
        on et.EmployerId = ei.EmployerId
        and et.QId = q.QId
join employer as e
        on e.EmployerId = ei.EmployerId
where et.employerid is null
group by ei.employerid,q.QId
order by ei.EmployerId,q.QId

查询结果如下：

    EmployerId   EmployerName                 QId
    1            Potato Inc                   20193
    1            Potato Inc                   20202
    1            Potato Inc                   20203
    2            Donuts LLC                   20202
    2            Donuts LLC                   20203
    3            Pineapple Logistics          20191
    3            Pineapple Logistics          20192
    3            Pineapple Logistics          20193
    3            Pineapple Logistics          20194

我想要的是将 QId 列合并为每个 EmployerId 的一行，如下所示：

     EmployerId   EmployerName                 QId
     1            Potato Inc                   20193,20202,20203
     2            Donuts LLC                   20202,20203
     3            Pineapple Logistics          20191,20192,20193,20194

我使用的是 sql Server 2016，所以很遗憾我无法利用 string_agg()，必须使用 FOR XML 和 stuff()。我不确定如何在具有多个连接的查询上使用 stuff()。任何帮助表示赞赏。

解决方法

这是for xml path 子句在起作用。 stuff 只是去掉开头的 ','

with sampledata as (
   -- your original query here
)
select EmployerId,EmployerName,stuff( (select ','+ cast(t2.Qid as varchar(5))
          from sampledata t2
          where t2.EmployerId = t1.EmployerId and t2.EmployerName = t1.EmployerName
          for xml path ('')),1,'') qids
from sampledata t1
group by EmployerId,EmployerName

db<>fiddle

退货

EmployerId  EmployerName    qids
1   Potato Inc  20193,20202,20203
2   Donuts LLC  20202,20203
3   Pineapple Logistics 20191,20192,20193,20194

试试这个解决方案

Select  ei.EmployerId,e.EmployerName,ISNULL(STUFF((Select Distinct ',' + Cast(QId  As Varchar(500))
                        From employerTransaction As Q
                        Where  et.QId = q.QId
                        FOR XML PATH('')),''),'-') As [NewQID]
From employerIds As ei
Left Join employerTransaction as et on et.EmployerId = ei.EmployerId and et.QId = q.QId
Join employer as e on e.EmployerId = ei.EmployerId
Where et.employerid is null
Group By ei.employerid,e.EmployerName