Question

I am trying to replicate a table produced from a sybase database, I dont have the code but have access to the database.

I have reproduced the table almost perfectly, but because I used a union I have duplicate rows where they should have merged:

select distinct id, dn, pn, null as sp
from dn
union
select id, 'DN', 'PN', sp
from sp
order by id

But I produce, for example:

 pn,    dn,         pn,          sp

'110','Liversage','Consultant', null

'110','DN       ','PN        ','Cardiac'

Basically I wanted the null to be filled with cardiac and the DN and PN and row two to be merged into row one?

Answer 1

Why not do something like this:

SELECT ID, COALESCE(A.dn, B.dn), COALESCE(A.pn, B.pn), COALESCE(A.sp,B.sp)
FROM dn A
    LEFT OUTER JOIN sp B
         ON A.id = B.id 

Which will pick the first non-null value from each table. I have limited knowledge of your tables to give a complete answer, but you’re likely to have better luck with this approach as union doesn’t do what you seem to want it to do.