mysql - 子查询和连接 - 无法绑定(bind)多部分标识符

Question

我是一个新代码，无法让子查询处理主查询数据。本质上，我想从结果中计算出有多少台电脑是 HP 电脑。当我运行它时，出现错误:无法绑定(bind)多部分标识符“dbo.softwareapplications.softwareid”。

select distinct appname, version, linkid,
(select count(make) as totalhp from dbo.workstations where make = 'Hewlett-Packard' and linkdid = t1.linkid)as totalhp
from dbo.softwareapplications as t1
join dbo.assignments on dbo.softwareapplications.softwareid = dbo.IQCSassignments.softwareid
join dbo.workstations on dbo.assignments.wsid = dbo.workstations.wsid
group by assetdescription, version, linkid, totalhp

如有任何帮助，我们将不胜感激。

Answer 1

由于您已将“dbo.softwareapplications”表别名为 t1，因此您必须在后续子句中引用它:

join dbo.assignments on t1.softwareid = dbo.IQCSassignments.softwareid

(或者，删除“as t1”别名和对其的其他引用。)