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    <p>Something like this, if I've understood you correctly</p> <pre><code>SELECT MAX(CREATIONTIME), A.AID FROM A INNER JOIN B ON A.AID = B.AID INNER JOIN C ON B.CID = C.CID WHERE A.STATUS = 'OK' GROUP BY A.AID </code></pre> <p><strong>EDIT:</strong></p> <p>I have now checked the following in SQL Server (I would epxect the same outcome in Oracle) and it returns the <code>CID</code> for the <code>C</code> record with the Maximum <code>CREATIONTIME</code> where the <code>STATUS</code> for the related record in <code>A</code> id <code>'OK'</code>.</p> <pre><code>SELECT C.CID FROM C C INNER JOIN B B ON C.CID = B.CID INNER JOIN ( SELECT MAX(C.CREATIONTIME) CREATIONTIME, A.AID FROM A A INNER JOIN B B ON A.AID = B.AID INNER JOIN C C ON B.CID = C.CID WHERE A.STATUS = 'OK' GROUP BY A.AID ) ABC ON B.AID = ABC.AID AND C.CREATIONTIME = ABC.CREATIONTIME </code></pre> <p>Demonstrated with the following <strong><em>T-SQL</em></strong></p> <pre><code>DECLARE @A TABLE(AID INT IDENTITY(1,1), STATUS VARCHAR(10)) DECLARE @B TABLE(BID INT IDENTITY(1,1), AID INT, CID INT) DECLARE @C TABLE(CID INT IDENTITY(1,1), CREATIONTIME DATETIME) INSERT INTO @A VALUES ('OK') INSERT INTO @A VALUES ('OK') INSERT INTO @A VALUES ('NOT OK') INSERT INTO @A VALUES ('OK') INSERT INTO @A VALUES ('NOT OK') INSERT INTO @C VALUES ('10 MAR 2008') INSERT INTO @C VALUES ('13 MAR 2008') INSERT INTO @C VALUES ('15 MAR 2008') INSERT INTO @C VALUES ('17 MAR 2008') INSERT INTO @C VALUES ('21 MAR 2008') INSERT INTO @B VALUES (1,1) INSERT INTO @B VALUES (1,2) INSERT INTO @B VALUES (1,3) INSERT INTO @B VALUES (2,2) INSERT INTO @B VALUES (2,3) INSERT INTO @B VALUES (2,4) INSERT INTO @B VALUES (3,3) INSERT INTO @B VALUES (3,4) INSERT INTO @B VALUES (3,5) INSERT INTO @B VALUES (4,5) INSERT INTO @B VALUES (4,1) INSERT INTO @B VALUES (4,2) SELECT C.CID FROM @C C INNER JOIN @B B ON C.CID = B.CID INNER JOIN ( SELECT MAX(C.CREATIONTIME) CREATIONTIME, A.AID FROM @A A INNER JOIN @B B ON A.AID = B.AID INNER JOIN @C C ON B.CID = C.CID WHERE A.STATUS = 'OK' GROUP BY A.AID ) ABC ON B.AID = ABC.AID AND C.CREATIONTIME = ABC.CREATIONTIME </code></pre> <p>Results in the following</p> <pre><code>CID ----------- 3 4 5 </code></pre> <p><strong>EDIT 2:</strong></p> <p>In response to your comment about each of the statements giving different results, I have ran some of the different answers here through SQL Server 2005 using my test data above (I appreciate you are using Oracle). Here are the results</p> <pre><code>--Expected results for CIDs would be --CID ----------- --3 --4 --5 --As indicated in the comments next to the insert statements DECLARE @A TABLE(AID INT IDENTITY(1,1), STATUS VARCHAR(10)) DECLARE @B TABLE(BID INT IDENTITY(1,1), AID INT, CID INT) DECLARE @C TABLE(CID INT IDENTITY(1,1), CREATIONTIME DATETIME) INSERT INTO @A VALUES ('OK') -- AID 1 INSERT INTO @A VALUES ('OK') -- AID 2 INSERT INTO @A VALUES ('NOT OK') INSERT INTO @A VALUES ('OK') -- AID 4 INSERT INTO @A VALUES ('NOT OK') INSERT INTO @C VALUES ('10 MAR 2008') INSERT INTO @C VALUES ('13 MAR 2008') INSERT INTO @C VALUES ('15 MAR 2008') INSERT INTO @C VALUES ('17 MAR 2008') INSERT INTO @C VALUES ('21 MAR 2008') INSERT INTO @B VALUES (1,1) INSERT INTO @B VALUES (1,2) INSERT INTO @B VALUES (1,3) -- Will be CID 3 For AID 1 INSERT INTO @B VALUES (2,2) INSERT INTO @B VALUES (2,3) INSERT INTO @B VALUES (2,4) -- Will be CID 4 For AID 2 INSERT INTO @B VALUES (3,3) INSERT INTO @B VALUES (3,4) INSERT INTO @B VALUES (3,5) INSERT INTO @B VALUES (4,5) -- Will be CID 5 FOR AID 4 INSERT INTO @B VALUES (4,1) INSERT INTO @B VALUES (4,2) -- Russ Cam SELECT C.CID, ABC.CREATIONTIME FROM @C C INNER JOIN @B B ON C.CID = B.CID INNER JOIN ( SELECT MAX(C.CREATIONTIME) CREATIONTIME, A.AID FROM @A A INNER JOIN @B B ON A.AID = B.AID INNER JOIN @C C ON B.CID = C.CID WHERE A.STATUS = 'OK' GROUP BY A.AID ) ABC ON B.AID = ABC.AID AND C.CREATIONTIME = ABC.CREATIONTIME -- Tyrannosaurs select A.AID, max(AggC.CREATIONTIME) from @A A, @B B, ( select C.CID, max(C.CREATIONTIME) CREATIONTIME from @C C group by CID ) AggC where A.AID = B.AID and B.CID = AggC.CID and A.Status = 'OK' group by A.AID -- jmucchiello SELECT c.cid, max(c.creationtime) FROM @B b, @C c WHERE b.cid = c.cid AND b.aid IN (SELECT a.aid FROM @A a WHERE status = 'OK') GROUP BY c.cid -- hainstech SELECT agg.aid, agg.cid FROM ( SELECT a.aid ,c.cid ,max(c.creationtime) as maxcCreationTime FROM @C c INNER JOIN @B b ON b.cid = c.cid INNER JOIN @A a on a.aid = b.aid WHERE a.status = 'OK' GROUP BY a.aid, c.cid ) as agg --chris SELECT A.AID, C.CID, C.CREATIONTIME FROM @A A, @B B, @C C WHERE A.STATUS = 'OK' AND A.AID = B.AID AND B.CID = C.CID AND C.CREATIONTIME = (SELECT MAX(C2.CREATIONTIME) FROM @C C2, @B B2 WHERE B2.AID = A.AID AND C2.CID = B2.CID); </code></pre> <p>the results are as follows</p> <pre><code>--Russ Cam - Correct CIDs (I have added in the CREATIONTIME for reference) CID CREATIONTIME ----------- ----------------------- 3 2008-03-15 00:00:00.000 4 2008-03-17 00:00:00.000 5 2008-03-21 00:00:00.000 --Tyrannosaurs - No CIDs in the resultset AID ----------- ----------------------- 1 2008-03-15 00:00:00.000 2 2008-03-17 00:00:00.000 4 2008-03-21 00:00:00.000 --jmucchiello - Incorrect CIDs in the resultset cid ----------- ----------------------- 1 2008-03-10 00:00:00.000 2 2008-03-13 00:00:00.000 3 2008-03-15 00:00:00.000 4 2008-03-17 00:00:00.000 5 2008-03-21 00:00:00.000 --hainstech - Too many CIDs in the resultset, which CID has the MAX(CREATIONTIME) for each AID? aid cid ----------- ----------- 1 1 1 2 1 3 2 2 2 3 2 4 4 1 4 2 4 5 --chris - Correct CIDs, it is the same SQL as mine AID CID CREATIONTIME ----------- ----------- ----------------------- 1 3 2008-03-15 00:00:00.000 2 4 2008-03-17 00:00:00.000 4 5 2008-03-21 00:00:00.000 </code></pre> <p>I would recommend running each of the given answers against a smaller number of records, so that you can ascertain whether the resultset returned is the expected one.</p>
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    1. COThat's very close, but it does not return the C.CID which is the only column I'm interested in.
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    2. COThank you for your effort! I will try it soon, but I don't understand how the select statement in inner join work in this case? How does it take into account the indirect relationship between tables A and C? I just don't get it.
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    3. CORuss, I really appreciate your effort! It's a national holiday today so I won't verify it thoroughly, but I studied quite closely the query and it made sense, and I was able to get it running on Oracle. Also the number of rows it returns in our relatively big database seems very reasonable.
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