How can I select a subset of columns from a table when relevant in an outer join?

select a.cust_xref_id, a.est_hour, a.phone_nbr as number, a.credit_calls, a.credit_rpcs, b.sdp_calls
from #temp0 a
full outer join #temp2 b
on a.cust_xref_id = b.sdp_cust_xref_id
and a.est_hour = b.sdp_hour
and a.phone_nbr = b.sdp_phone

Is there a way to get the data from table b with regard to sdp_cust_xref_id, sdp_hour, and sdp_phone when the data does not ex开发者_运维技巧ist in both tables via the join? If b.sdp_calls does exist, the column values are null.

I read it a few more times and I think I know what you want. Try this. It will give you the values from table b if they are NULL in a:

select  COALESCE(a.cust_xref_id, b.sdp_cust_xref_id) as cust_xref_id,
        COALESCE(a.est_hour, b.spd_hour) as est_hour,
        COALESCE(a.phone_nbr, b.spd_phone) as number, 
        a.credit_calls, 
        a.credit_rpcs, 
        b.sdp_calls
from #temp0 a
full outer join #temp2 b
on a.cust_xref_id = b.sdp_cust_xref_id
and a.est_hour = b.sdp_hour
and a.phone_nbr = b.sdp_phone