little help with some tsql

Given following table:

rowId  AccountId  Organization1  Organization2
-----------------------------------------------
1  开发者_如何学编程    1          20             10
2      1          10             20
3      1          40             30
4      2          15             10
5      2          20             15
6      2          10             20

How do I identify the records where Organization2 doesn't exist in Organization1 for a particular account

for instance, in the given data above my results will be a single record which will be AccountId 1 because row3 organization2 value 30 doesn't exist in organization1 for that particular account.

SELECT rowId, AccountId, Organization1, Organization2
FROM   yourTable yt
WHERE  NOT EXISTS (SELECT 1 FROM yourTable yt2 WHERE yt.AccountId = yt2.AccountId AND yt.Organization1 = yt2.Organization2)

There are two possible interpretations of your question. The first (where the Organization1 and Organization2 columns are not equal) is trivial:

SELECT AccountID FROM Table WHERE Organization1 <> Organization2

But I suspect you're asking the slightly more difficult interpretation (where Organization2 does not appear in ANY Organization1 value for the same account):

SELECT AccountID From Table T1 WHERE Organization2 NOT IN 
  (SELECT Organization1 FROM Table T2 WHERE T2.AccountID = T1.AccountID)

Here is a how you could do it:

Test data:

CREATE TABLE #T(rowid int, acc int, org1 int, org2 int)

INSERT #T
SELECT 1,1,10,10  UNION
SELECT 2,1,20,20   UNION
SELECT 3,1,40,30   UNION
SELECT 4,2,10,10   UNION
SELECT 5,2,15,15   UNION
SELECT 6,2,20,20

Then perform a self-join to discover missing org2:

SELECT
*
FROM #T T1
LEFT JOIN
    #T T2
 ON t1.org1 = t2.org2
AND t1.acc = t2.acc

WHERE t2.org1 IS NULL

SELECT
    *
FROM
    [YorTable]
WHERE
    [Organization1] <> [Organization2]  -- The '<>' is read "Does Not Equal".

Use left join as Noel Abrahams presented.