SQL，CUCM:查询返回没有结果

Question

以下CUCM (11.5) cli中的SQL查询返回如下结果：

device          number          loggedin_to_lg linegroup
=============== =============== ============== ======================================
CSFABCDEF      \+49325874147  f              LG-HG_BER01_49325874147      
CSFRFETRS      \+49325800848  f              LG-HG_BER01_493225800848

run sql select d.name as Device, n.dnorpattern as Number, dhd.hlog as LoggedIn_to_LG, lg.name as LineGroup 
from linegroup as lg 
inner join linegroupnumplanmap as lgmap on lgmap.fklinegroup=lg.pkid 
inner join numplan as n on lgmap.fknumplan = n.pkid 
inner join devicenumplanmap as dmap on dmap.fknumplan=n.pkid 
inner join device as d on dmap.fkdevice=d.pkid 
inner join devicehlogdynamic as dhd on dhd.fkdevice=d.pkid 
order by lg.name 

但是，如果我们试图将另一个表--扩展移动动态表--内部连接到这个查询并显示它的一个列，它就不会返回结果。

run sql select d.name as Device, n.dnorpattern as Number, dhd.hlog as LoggedIn_to_LG, lg.name as LineGroup, e.datetimestamp 
from linegroup as lg 
inner join linegroupnumplanmap as lgmap on lgmap.fklinegroup=lg.pkid 
inner join numplan as n on lgmap.fknumplan = n.pkid 
inner join devicenumplanmap as dmap on dmap.fknumplan=n.pkid 
inner join device as d on dmap.fkdevice=d.pkid 
inner join devicehlogdynamic as dhd on dhd.fkdevice=d.pkid 
inner join extensionmobilitydynamic as e on e.fkdevice = d.pkid 
order by lg.name 

Answer 1

它没有找到任何匹配的行，因此内部联接无法检索任何内容。如果没有匹配的结果，则必须为新表尝试左联接。结果列在此实例中为空。

run sql select d.name as Device, n.dnorpattern as Number, dhd.hlog as LoggedIn_to_LG, lg.name as LineGroup, e.datetimestamp 
from linegroup as lg 
inner join linegroupnumplanmap as lgmap on lgmap.fklinegroup=lg.pkid 
inner join numplan as n on lgmap.fknumplan = n.pkid 
inner join devicenumplanmap as dmap on dmap.fknumplan=n.pkid 
inner join device as d on dmap.fkdevice=d.pkid 
inner join devicehlogdynamic as dhd on dhd.fkdevice=d.pkid 
left join extensionmobilitydynamic as e on e.fkdevice = d.pkid 
order by lg.name