檢索單值僅

Question

select fap.provider_id where fap.LOB = 'WMR' 

一些fap.provider_id有多個fap.LOB（「WMR，‘WMC’），怎麼只有一個fap.LOB檢索fap.provider_id）我只是想有一個fap.LOB提供商只要。

Answer 1

像這樣的東西應該工作。

select provider_id 
from  fap       -- I assume...??? 
group by lob       -- not sure if "lob" is a reserved word... check? 
having count(lob) = 1 
    and max(lob) = 'WMR' 
;