I have a situation where I need to link two tables together but the data may be in another (archive) table or different records are in both but I want the latest record from either table:
ACCOUNT
AccountID Name
123 John Doe
124 Jane Donaldson
125 Harold Douglas
MARKETER_ACCOUNT
Key AccountID Marketer StartDate EndDate
1001 123 10526 8/3/2008 9/27/2009
1017 123 10987 9/28/2009 12/31/4712 (high date ~ which means currently with this marketer)
1023 124 10541 12/03/2010 12/31/4712
ARCHIVE
Key AccountID Marketer StartDate EndDate
1015 124 10526 8/3/2008 12/02/2010
1033 125 10987 01/01/2011 01/31/2012
So my query needs to return the following:
123 John Doe 10526 8/3/2008 9/27/2009
124 Jane Donaldson 10541 12/03/2010 12/31/4712 (this is the later of the two records for this account between archive and marketer_account tables)
125 Harold Douglas 10987 01/01/2011 01/31/2012 (he is only in archive, so get this record)
I'm unsure how to proceed in one query. Note that I am reading in possibly multiple accounts at a time and returning a collection back to .net
open CURSOR_ACCT
select AccountID
from
ACCOUNT A,
MARKETER_ACCOUNT M,
ARCHIVE R
where A.AccountID = nvl((select max(M.EndDate) from Marketer_account M2
where M2.AccountID = A.AccountID),
(select max(R.EndDate) from Archive R2
where R2.AccountID = A.AccountID)
and upper(A.Name) like parameter || '%'
<can you do a NVL like this? probably not... I want to be able to get the MAX record for that account off the MarketerACcount table OR the max record for that account off the Archive table, but not both>
(parameter could be "DO", so I return all names starting with DO...)