查詢結果爲空結果

Question

我想下面的查詢

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

查詢成功運行，但是，儘管我有eid's這等於一些competence_id's和where子句返回任何結果也是如此

其實，即使沒有where條款，它也不起作用！

編輯：這樣做解決了這個問題：

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返回一個字符串。根據您的SQL味道，你應該嘗試

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

試試這個代碼：

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