查询结果为空结果

Question

我想下面的查询

`select 
skillmgt.*, competences.Competence_Description 
from skillmgt 
inner join competences 
on skillmgt.eid=competences.competence_id 
where eid=121 and datename(yyyy,timestamp)=2013` 

查询成功运行，但是，尽管我有eid's这等于一些competence_id's和where子句返回任何结果也是如此

其实，即使没有where条款，它也不起作用！

编辑：这样做解决了这个问题：

select skillmgt.*,competences.* from competences 
join skillmgt 
on competences.competence_id=skillmgt.cid 
where skillmgt.eid=121 and datename(yyyy,skillmgt.timestamp)='2013' 

Answer 1

datename返回一个字符串。根据您的SQL味道，你应该尝试

select 
skillmgt.*, competences.Competence_Description 
from skillmgt 
inner join competences 
on skillmgt.eid=competences.competence_id 
where eid=121 and datename(yyyy,timestamp)="2013" 

Answer 2

试试这个代码：

select 
skillmgt.*, competences.Competence_Description 
from skillmgt,competences 
where skillmgt.eid = competences.competence_id 
...