mysql返回多行的单行和状态

Question

对于模糊的问题标题道歉，但对正确的措辞不确定，如果需要，请更正。

我有以下MySQL查询，它将我的几个表连接在一起。

select distinct(o.person), 
    o.job,
    p.risk,
    r.training,
    case when c.datecompleted  is null then 'no' else 'yes' end TrainingCompleted,
    case when c.expirydate is null then '' else c.expirydate end expirydate
from 
    orgstructure o 
    join personrisks p on p.Person=o.person
    right outer join risktraining r on r.risk=p.risk
    left outer join coursescompleted c on c.course=r.training and c.person=o.person
where o.department='house keeping' and o.person <> ''
order by o.person desc

它产生以下结果：

在结果中，您可以看到每种风险都有两种解决风险的培训解决方案。我想返回另一个列status，该列查看每个培训和培训已完成的字段，如果其中一个培训已完成，则状态为good，状态为bad。所以我的输出在这个例子中只有两行用于每个风险。如果没有完成任何培训，则显示需要的任何training值。

理想输出：

如何编辑此查询以获得所需结果。

提前致谢。

Answer 1

最简单的方法是

select 
    o.person,
    o.job,
    p.risk,
    case when count(c.datecompleted) > 0 then null else r.training end as training,
    case when count(c.datecompleted) > 0 then 'yes' else 'no' end as TrainingCompleted,
    case when count(c.datecompleted) > 0 then 'good' else 'bad' end as Status
from orgstructure o 
    join personrisks p on p.Person=o.person
    right outer join risktraining r on r.risk=p.risk
    left outer join coursescompleted c on c.course=r.training and c.person=o.person
where o.department='house keeping' and o.person <> ''
group by o.person
order by o.person desc, case when c.datecompleted is not null then 0 else 1 end asc

如果任何训练完成，我不会在训练中显示训练。

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