Need Help--Derived Tables???

Question

Need Help--Derived Tables???

bharathi-903755

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Points: 425
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October 8, 2008 at 10:45 pm

#199134

Hello All!!!
I need to take diff of two dates,comapring two other columns,row by row.So,I have used Cursor for that,its is working fine...But its taking time.
I did find tht cursors can be replaced with derived tables.
I am new to SQL...I m gving the code here
Please Help!!!
USE HR_Recruitment_Operational_Reports_StagingDb
DECLARE @a AS DATETIME ,@B AS DATETIME,@C AS BIGINT,@D AS BIGINT,@Id AS BIGINT
DECLARE MyCursor CURSOR FOR SELECT MIN(RIV_ID),MAX(RIV_ID),RIV_RCN_ID FROM ABACUSNEWDATA_REC_INTERVIEW GROUP BY RIV_RCN_ID
OPEN MyCursor
FETCH NEXT FROM MyCursor
INTO @C,@D,@Id
WHILE @@FETCH_STATUS = 0
BEGIN
SET @a = (SELECT RIV_CREATED_ON FROM ABACUSNEWDATA_REC_INTERVIEW WHERE RIV_ID = @C)
SET @b-2 = (SELECT RIV_CREATED_ON FROM ABACUSNEWDATA_REC_INTERVIEW WHERE RIV_ID = @D)
print (@Id) print(DATEDIFF(day,@A,@B)) --FROM ABACUS_REC_INTERVIEW --GROUP BY RIV_RCN_ID
FETCH NEXT FROM MyCursor
INTO @C,@D,@Id
END
CLOSE MyCursor
DEALLOCATE MyCursor

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ChrisM@Work SSC Guru Points: 186127 More actions · Answer 1

Hello

This is also untested but should be pretty close to what you're looking for - if it isn't, please post DDL of your table and some sample data.

[font="Courier New"]SELECT d1.RIV_RCN_ID, DATEDIFF(DAY, d2.RIV_CREATED_ON, d3.RIV_CREATED_ON)

FROM (SELECT MIN(RIV_ID) AS MIN_RIV_ID, MAX(RIV_ID) AS MAX_RIV_ID, RIV_RCN_ID

FROM ABACUSNEWDATA_REC_INTERVIEW

GROUP BY RIV_RCN_ID) d1

INNER JOIN ABACUSNEWDATA_REC_INTERVIEW d2 ON d2.RIV_RCN_ID = d1.RIV_RCN_ID AND d2.RIV_ID = d1.MIN_RIV_ID

INNER JOIN ABACUSNEWDATA_REC_INTERVIEW d3 ON d3.RIV_RCN_ID = d1.RIV_RCN_ID AND d3.RIV_ID = d1.MAX_RIV_ID

[/font]

Wandrag - your solution assumes that the min and max RIV_CREATED_ON per RIV_RCN_ID is the same thing as the RIV_CREATED_ON on the min RIV_ID row and max RIV_ID row per RIV_RCN_ID. They may not be the same.

Cheers

ChrisM

^{“Write the query the simplest way. If through testing it becomes clear that the performance is inadequate, consider alternative query forms.” - Gail Shaw}

For fast, accurate and documented assistance in answering your questions, please read this article.
Understanding and using APPLY, (I) and (II) Paul White
Hidden RBAR: Triangular Joins / The "Numbers" or "Tally" Table: What it is and how it replaces a loop Jeff Moden

bharathi-903755 SSC-Addicted Points: 425 More actions · Answer 2

bharathi-903755

SSC-Addicted

Points: 425

October 9, 2008 at 6:26 am

#882836

I found it myself...Thankss a lot anywayz...

ChrisM@Work SSC Guru Points: 186127 More actions · Answer 3

bharathi (10/9/2008)
I found it myself...Thankss a lot anywayz...

Hi bharathi

Please would you post your solution? It would finish this thread nicely and also, possibly, provide useful learning material for others.

Cheers

ChrisM

^{“Write the query the simplest way. If through testing it becomes clear that the performance is inadequate, consider alternative query forms.” - Gail Shaw}

For fast, accurate and documented assistance in answering your questions, please read this article.
Understanding and using APPLY, (I) and (II) Paul White
Hidden RBAR: Triangular Joins / The "Numbers" or "Tally" Table: What it is and how it replaces a loop Jeff Moden

Jeff Moden SSC Guru Points: 1004312 More actions · Answer 4

bharathi (10/9/2008)
I found it myself...Thankss a lot anywayz...

Two way street here... would you please post your solution? Thanks. 🙂

--Jeff Moden

RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
First step towards the paradigm shift of writing Set Based code:
________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

Change is inevitable... Change for the better is not.

Helpful Links:
How to post code problems
How to Post Performance Problems
Create a Tally Function (fnTally)

bharathi-903755 SSC-Addicted Points: 425 More actions · Answer 5

Hi Chris!!!

I could do the same way as wandrag did without derived tables...

And I tried ur query..it worked perfectly....

Thanku for ur Help.....

Regards,