Oracle 10 SQL: FULL JOIN through Cross Reference Table - sql

Question

http://sqlfiddle.com/#!4/24637/1
I have three tables, (better details/data shown in sqlfiddle link), one replacing another, and a cross reference table in between. One of the fields in each of the table uses the cross reference (version), and another one of the fields in each of the tables is the same (changeID).
I need a query that when passed a list of new_version + new_changeType, along with the equivalent original_version + old_changeType (if there is an old version equivalent) PLUS any old changeIDs that were 'missed' in the conversion of data.
TABLES (fields on the same line are equivalent)
OLD_table | XREF_table | NEW_Table
original_version | original_version |
changeID | | changeID
OLD_changeType | |
| new_version | new_version
| | NEW_changeType
DATA
111,1,CT1 | 111,AAA | AAA,1,ONE
111,2,CT2 | 222,BBB | AAA,2,TWO
222,1,CT1 | 333,DDD | BBB,1,ONE
222,2,CT2 | | BBB,2,TWO
222,3,CT3 | | CCC,1,ONE
333,1,CT1 | |
444,1,CT1 | |
If passed the following list, the result set should look like so. (order doesnt matter)
AAA,BBB,CCC
| NEW_VERSION | NEW_CHANGE_TYPE| ORIGINAL_VERSION | CHANGEID | OLD_CHANGE_TYPE |
|-------------|----------------|------------------|----------|-----------------|
| AAA | ONE | 111 | 1 | CT1 |
| AAA | TWO | 111 | 2 | CT2 |
| BBB | ONE | 222 | 1 | CT1 |
| BBB | TWO | 222 | 2 | CT2 |
| CCC | ONE | (null) | (null) | (null) |
| (null) | (null) | 222 | 3 | CT3 |
I'm having trouble getting ALL the data required. I've played with the following query, however I seem to either 1) miss a row or 2) get additional rows not matching the requirements.
The following queries I've played with are as follows.
select
a.new_version,
a.Change_type,
c.original_version,
c.changeID,
c.OLD_Change_type
from NEW_TABLE a
LEFT OUTER JOIN XREF_TABLE b on a.new_version = b.new_version
FULL OUTER JOIN OLD_TABLE c on
b.original_version = c.original_version and a.changeID = c.changeID
where (b.new_version in ('AAA','BBB','CCC') or b.new_version is null);
select
a.new_version,
a.Change_type,
c.original_version,
c.changeID,
c.OLD_Change_type
from NEW_TABLE a
FULL JOIN XREF_TABLE b on a.new_version = b.new_version
FULL JOIN OLD_TABLE c on
b.original_version = c.original_version and a.changeID = c.changeID
where (a.new_version in ('AAA','BBB','CCC'));
The first returns one 'extra' row with the 333,DDD data, which is not specified from the input.
The seconds returns one less row (with the changeID from the old table "missed" from when this data was converted over.
Any thoughts or suggestions on how to solve this?

Answer 1

First inner join old_table and xref_table, as you are not interested in any old_table entries without an xref_table entry. Then full outer join new_table. In your WHERE clause be aware that new_table.new_version can be null, so use coalesce to use xref_table.new_version in this case to limit your results to AAA, BBB and CCC. That's all.
select
coalesce(n.new_version, x.new_version) as new_version,
n.change_type,
o.original_version,
o.changeid,
o.old_change_type
from old_table o
inner join xref_table x
on x.original_version = o.original_version
full outer join new_table n
on n.new_version = x.new_version
and n.changeid = o.changeid
where coalesce(n.new_version, x.new_version) in ('AAA','BBB','CCC')
order by 1,2,3,4,5
;
Here is your fiddle: http://sqlfiddle.com/#!4/24637/11.
BTW: Better never use random aliases like a, b and c that don't indicate what table is meant. That makes the query harder to understand. Use the table's first letter(s) or an acronym instead.