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Problem with SQL Server Cursors

Hi,
I am nesting 2 cursors,
First Cursor retrieves ID's from 1 table,
Second(Inner) Cursor retrieves IDs from temp table
Within the Inner Cursor I do some evaluations and
Insert to a table.
Then when done, loop the outer cursor to the next ID and do the inner cursor stuff again.

I am experiencing problems with both Cursors at different times. Sometimes the Outer Cursor does not seem to finish looping through, leaving out the last ID, sometimes the Inner Cursor doesnt seem to finish. I can't for the life of me figure this out.

Weirdest thing is, when I step through this in the debugger in both Interdev and SQL Server Management Console, It runs perfectly. I only have 170 points so thats all I can offer, but if anyone has a sec that can peak at the following code and give me any ideas, I would greatly appreciate it. I have been working this problem from so many agles for 3 days now and can't get it to work right.

Is there any specific things to watch out for when nesting cursors? Could the @@FETCH_STATUS from the inner Cursor be screwing with the outer Cursor?

Thanks,


DECLARE RECUR_CURSOR CURSOR FOR
Select ID from Recurrence where eventID = @eventID
Open RECUR_CURSOR
FETCH NEXT FROM RECUR_CURSOR INTO @recurID
WHILE @@FETCH_STATUS = 0
Begin

Declare CalUser_Cursor Cursor FOR
Select CalID from #CalUserID order by CalID asc
Open CalUser_Cursor
Fetch Next From CalUser_Cursor into @CalUID
While @@Fetch_Status = 0

      Begin
                                                  Select @calCnt = count(ID) from TestTable
where RecurID = recurID and CalID = @CalUID

IF @calCnt < 1
                                                  Begin
            Insert into TestTable(RecurID, CalID)
            Values(@recurID, @CalUID)
       End
      Fetch Next From CalUser_Cursor into @CalUID
      End
      Close CalUser_Cursor


FETCH NEXT FROM RECUR_CURSOR INTO @recurID
END

ASKER CERTIFIED SOLUTION

Dexstar

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Dexstar

jshillm,

Try this query:
      SELECT
            R.ID As RecID,
            C.CalID
      FROM
            Recurrence R,
            #CalUserID C
      WHERE
            R.ID NOT IN (SELECT RecurID FROM TestTable WHERE CalID = C.CalID)
      ORDER BY
            CalID ASC

It *SHOULD* return all the rows that need to be inserted into TestTable. But its the end of the day, and I could've messed up the query. If it works, then you can modify it to this, and you'll be done without any cursors at all.

      SELECT
            R.ID As RecID,
            C.CalID
      INTO
            TestTable
      FROM
            Recurrence R,
            #CalUserID C
      WHERE
            R.ID NOT IN (SELECT RecurID FROM TestTable WHERE CalID = C.CalID)
      ORDER BY
            CalID ASC

Hope this helps,
Dex*

Dexstar

Okay, since I don't know if what I gave you will work or not, I went ahead and wrote up another approach. If the other one doesn't work, try this one instead.

      SELECT
            R.ID As RecID,
            C.CalID
      FROM
            Recurrence R,
            #CalUserID C
      WHERE
            CHECKSUM(R.ID, C.CalID) NOT IN (SELECT CHECKSUM(RecurID, CalID) FROM TestTable)
      ORDER BY
            CalID ASC

But that will only work on SQL 2000. Is that an issue?

Dex*

SOLUTION

xenon_je

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Dexstar

jshillm,

Before, I forgot to filter on @eventID:
SELECT
R.ID As RecID,
C.CalID
FROM
Recurrence R,
#CalUserID C
WHERE
R.ID NOT IN (SELECT RecurID FROM TestTable WHERE CalID = C.CalID)
AND
R.EventID = @eventID
ORDER BY
CalID ASC

You should use the query analyzer to try all of these suggestions. Some of them may be faster that the others.

Dex*

jschillm

ASKER

Hi Guys,

Thanks so much for your quick feed back, both answers pointed me in the right direction and helped out tons.

When I tested Dex's solution, it almost did what I wanted, it brought up all of the records that needed to be inserted, if none had been inserted for a given CALID, however if there were 5 RecurIDs and there was 1 RecurID associated with the CalID, it did not show the 4 recurIDs that still needed to be inserted. It did help me though and give me pointers,

I used Xenon Joe's ansswer with a little modification, and it gave me exactly what I was looking for. One thing though, I did get an error when having the 'Order By' clause in a subquery, so i took it out.

I would have like to have split the points, but I did not get the option when I accepted the answer, any way of doing this after the fact?

PS, Is it possible to Delete from a table using similar code above?

Dexstar

I think you can split the points after the fact if you ask the moderators to help you.

Post a comment in Community Support and tell them what you'd like to do, and include a link to this question so they know which one to deal with.

Community Support
https://www.experts-exchange.com/Community_Support/

This Question
https://www.experts-exchange.com/questions/20775204/Problem-with-SQL-Server-Cursors.html

Glad you got it working,
Dex*

xenon_je

yap....you can also delete using a code similar to the above... if you have problems post it here and I will help you solve it...

good luck,
xenon

PS: thx :)