这是个多表外连接的问题，这是informix的写法，现在应用要签到Oracle中，总是写不对，表太多了，望高手指教一二
- SQL code
select a.int_id,a.omc_id,b.msc_name,a.timestamp,a.routeset_id,c.linkset_id,a.routeset_id,a.routeset_priority,d.national_network_dpc,b.dest_spcfrom c_hua_MSCServerMTP3SignallingRoute a,c_hua_msc_info b,outer c_hua_linkset c,outer c_hua_SignallingPoint dwhere a.msc_fdn = b.fdn and a.linkset_index = c.linkset_index and a.signallingpoint_fdn = d.fdn and a.msc_fdn = c.msc_fdn
------解决方案--------------------
select
a.int_id,
a.omc_id,
b.msc_name,
a.timestamp,
a.routeset_id,
c.linkset_id,
a.routeset_id,
a.routeset_priority,
d.national_network_dpc,
b.dest_spc
from
c_hua_MSCServerMTP3SignallingRoute a,
c_hua_msc_info b,
full join c_hua_linkset c on a.linkset_index = c.linkset_index and a.msc_fdn = c.msc_fdn
full join c_hua_SignallingPoint d on a.signallingpoint_fdn = d.fdn
where a.msc_fdn = b.fdn ;
------解决方案--------------------
select
a.int_id,
a.omc_id,
b.msc_name,
a.timestamp,
a.routeset_id,
c.linkset_id,
a.routeset_id,
a.routeset_priority,
d.national_network_dpc,
b.dest_spc
from
c_hua_MSCServerMTP3SignallingRoute a,
c_hua_msc_info b,
c_hua_linkset c,
c_hua_SignallingPoint d
where
a.msc_fdn = b.fdn and
a.linkset_index = c.linkset_index and
a.signallingpoint_fdn = d.fdn and
a.msc_fdn = c.msc_fdn
------解决方案--------------------
从你写的sql来看，一a表为主表，可以把a的所有数据选出来。其他的有有没有数据都可以的。
select
a.int_id,
a.omc_id,
b.msc_name,
a.timestamp,
a.routeset_id,
c.linkset_id,
a.routeset_id,
a.routeset_priority,
d.national_network_dpc,
b.dest_spc
from
c_hua_MSCServerMTP3SignallingRoute a,
left outer join c_hua_msc_info on b a.msc_fdn = b.fdn
left outer join c_hua_linkset c on a.linkset_index = c.linkset_index
left outer join outer c_hua_SignallingPoint d on a.signallingpoint_fdn = d.fdn