How to bring together multiple delta tables? - sql

Question

I have a table with IDs and primary information. I also have two delta tables keyed on ID and date of change. I need to build a view that merges these three tables together indicating all changes over time.
Main Table:
ID Name
-- ------------------
1 Bob Jones
2 Dave Smith
First Attribute Table:
ID Date Attr1
-- ---------- -----
1 01/01/2013 25
1 02/15/2013 33
1 02/17/2013 47
1 03/02/2013 58
2 02/01/2013 1
...
Second Attribute Table
ID Date Attr2
-- ---------- -----
1 01/01/2013 ABC
1 01/05/2013 DEF
1 01/15/2013 RST
1 02/10/2013 XYZ
1 02/15/2013 Foo
1 03/05/2013 Blah
2 02/01/2013 Two
...
Based on that data, for Bob Jones, I need the view to return the following:
ID Name Date Attr1 Attr2
-- ----------- ---------- ----- -----
1 Bob Jones 01/01/2013 25 ABC
1 Bob Jones 01/05/2013 25 DEF
1 Bob Jones 01/15/2013 25 RST
1 Bob Jones 02/10/2013 25 XYZ
1 Bob Jones 02/15/2013 33 Foo
1 Bob Jones 02/17/2013 47 Foo
1 Bob Jones 03/02/2013 58 Foo
1 Bob Jones 03/05/2013 58 Blah
I tried outer joining the attribute tables to get all change values ordered by date and then used an outer join on the entire query with itself to get "prior" records:
with qry as (
select
rownum = ROW_NUMBER() OVER (ORDER BY m.ID, a.DATE),
m.ID,
m.Name,
a.DATE,
a.Attr1,
a.Attr2
from Main m
inner join (
select
COALESCE(a1.ID, a2.ID) as ID,
COALESCE(a1.LOAD_DATE, a2.LOAD_DATE) as LOAD_DATE,
a1.Attr1,
a2.Attr2
from Attributes1 a1
full outer join Attributes2 a2
on (a1.ID = a2.ID and a1.DATE = a2.DATE)
) a on (a.ID = m.ID)
)
select
COALESCE(qry.ID, prev.ID) as ID,
COALESCE(qry.Name, prev.Name) as Name,
COALESCE(qry.DATE, prev.DATE) as DATE,
COALESCE(qry.Attr1, prev.Attr1) as Attr1,
COALESCE(qry.Attr2, prev.Attr2) as Attr2,
from qry
left join qry prev
on (prev.rownum = qry.rownum - 1)
order by ID, DATE
However, that doesn't work when one attribute table changes quicker than the other because the attributes that didn't change are null in the results of the attribute table join and if two nulls show up back-to-back, the coalesce will return a null when I need the last non-null value that was in that column.
Can this even be done in a view in SQL Server 2012?