Problem joining tables in SQL - sql

Question

SELECT MID, FAD.FirstOpenedDate ,LCD.LastCloseDate
FROM mwMaster.dbo.Merchant M
JOIN (
SELECT MerchID, MIN(moddate) AS FirstOpenedDate
FROM mwMaster.dbo.MerchantStatusHistory
GROUP BY MerchID
) FAD ON FAD.MerchID = M.MerchID
LEFT JOIN (
SELECT MerchID, MAX(moddate) AS LastCloseDate
FROM mwMaster.dbo.MerchantStatusHistory
GROUP BY MerchID
) LCD ON LCD.MerchID = M.MerchID
JOIN (
SELECT merchid ,avg(Transactions) ,avg(Profit)
FROM mwMaster.dbo.ResidualSummary RS
WHERE RS.Date_Processed < LCD.LastCloseDate
GROUP BY Merchid
) R ON R.MerchID = M.MerchID
I am having trouble performing the following join. I have run into this problem before and used temp tables but would like to find out what I am doing wrong. Basically the line that is not working is the 3rd to last. The "< LCD.LastClostDate" says that it cannot be bound. Is it possible to use the value from LCD which I created in a nested query above (in that query I used the M table in a similar way but I didnt run into any issue)? I am thinking becasue the LCD table is dynamically created here it cannot be used in the nested query but this is just my guess.
Any ideas?
On a side note I have also seen people using a CROSS and OVER. Not to farmiliar with how this works but may be applicable here?

Answer 1

I think though haven't tested you can just change your JOIN to a CROSS APPLY in SQL 2005+
SELECT MID, FAD.FirstOpenedDate ,LCD.LastCloseDate
FROM mwMaster.dbo.Merchant M
JOIN (
SELECT MerchID, MIN(moddate) AS FirstOpenedDate
FROM mwMaster.dbo.MerchantStatusHistory
GROUP BY MerchID
) FAD ON FAD.MerchID = M.MerchID
LEFT JOIN (
SELECT MerchID, MAX(moddate) AS LastCloseDate
FROM mwMaster.dbo.MerchantStatusHistory
GROUP BY MerchID
) LCD ON LCD.MerchID = M.MerchID
CROSS APPLY(
SELECT merchid ,avg(Transactions) ,avg(Profit)
FROM mwMaster.dbo.ResidualSummary RS
WHERE RS.Date_Processed < LCD.LastCloseDate
GROUP BY Merchid
) R ON R.MerchID = M.MerchID
But it might be easier to use CTEs
WITH LCD AS (SELECT MerchID, MAX(moddate) AS LastCloseDate
FROM mwMaster.dbo.MerchantStatusHistory
GROUP BY MerchID),
R AS (
SELECT merchid ,avg(Transactions) ,avg(Profit)
FROM mwMaster.dbo.ResidualSummary RS
INNER JOIN LCD on
LCD.MERCHID = RS.MERCHID
WHERE RS.Date_Processed < LCD.LastCloseDate
GROUP BY Merchid
)
SELECT MID, FAD.FirstOpenedDate ,LCD.LastCloseDate
FROM mwMaster.dbo.Merchant M
JOIN (
SELECT MerchID, MIN(moddate) AS FirstOpenedDate
FROM mwMaster.dbo.MerchantStatusHistory
GROUP BY MerchID
) FAD ON FAD.MerchID = M.MerchID
LEFT JOIN LCD ON LCD.MerchID = M.MerchID
LEFT JOIN R ON R.MerchID = M.MerchID

Answer 2

I can't really test this without your data, but here's one way you could do it:
SELECT MID,
MIN(moddate) OVER (PARTITION BY MerchID) as FirstOpenedDate,
MAX(moddate) OVER (PARTITION BY MerchID) as LastCloseDate
FROM mwMaster.dbo.Merchant
HAVING DateProcessed < LastCloseDate