Please start any new threads on our new site at https://forums.sqlteam.com. We've got lots of great SQL Server experts to answer whatever question you can come up with.

 All Forums
 General SQL Server Forums
 New to SQL Server Programming
 Eliminating a Cartesian product

Author  Topic 

SergioM
Posting Yak Master

170 Posts

Posted - 2013-07-29 : 16:07:32
I have a SQL statement with two left outer joins which connects 3 tables. Vendors, Tracking & Activity. For whatever reason, even though each is a one-to-many relationship, I am able to join 2 tables (from Vendors to Tracking) without an issue. when I then join Activity, I get a Cartesian product.

I suspected that 'DISTINCT' would help, but it doesn't. Any ideas?

SELECT DISTINCT CASE 
WHEN `vendor`.`companyname` IS NULL then 'No Company Assigned'
ELSE `vendor`.`companyname`
END AS companyNameSQL, `tracking`.`pkgTracking`, CASE
WHEN `tracking`.`pkgStatus` = '0' then 'No Data'
WHEN `tracking`.`pkgStatus` = '1' then 'Initiated'
WHEN `tracking`.`pkgStatus` = '2' then 'In Transit'
WHEN `tracking`.`pkgStatus` = '3' then 'Delivery Exception'
END AS Status, `activity`.`dateUpdated` , `tracking`.`id` as tttiidd
FROM `tracking`
LEFT OUTER JOIN `vendor`
ON `tracking`.`vendorID` = `vendor`.`id`
LEFT OUTER JOIN `activity`
ON `activity`.`pkgTracking` = `tracking`.`pkgTracking`

WHERE `tracking`.`pkgStatus` !='4' AND `tracking`.`pkgStatus` !='5'


-Sergio
This is on MySQL

James K
Master Smack Fu Yak Hacker

3873 Posts

Posted - 2013-07-29 : 16:20:12
This forum is for Microsoft SQL Server, so there may be very few MySQL experts here. You might get faster and more accurate answers at a MySQL forum or other generalized forums such as dbforums.com

Looking from T-SQL perspective, I don't see anything wrong with the query unless you were not joining on all columns that you should when you join the activity table.
Go to Top of Page

Lamprey
Master Smack Fu Yak Hacker

4614 Posts

Posted - 2013-07-29 : 16:20:52
Maybe you need to add another column to your join or that's just how the data is. Hard to tell without any knowledge of your system.

http://www.sqlservercentral.com/articles/Best+Practices/61537/
http://weblogs.sqlteam.com/brettk/archive/2005/05/25/5276.aspx
Go to Top of Page

SwePeso
Patron Saint of Lost Yaks

30421 Posts

Posted - 2013-07-29 : 17:07:26
[code]SELECT COALESCE(v.CompanyName, 'No Company Assigned') AS companyNameSQL,
t.pkgTracking,
CASE
WHEN t.pkgStatus = '0' then 'No Data'
WHEN t.pkgStatus = '1' then 'Initiated'
WHEN t.pkgStatus = '2' then 'In Transit'
WHEN t.pkgStatus = '3' then 'Delivery Exception'
END AS [Status],
a.dateUpdated,
t.id AS tttiidd
FROM dbo.Tracking AS t
LEFT JOIN dbo.Vendor AS v ON v.id = t.vendorID
LEFT JOIN (
SELECT pkgTracking,
MAX(dateUpdated) AS dateUpdated
FROM dbo.Activity
GROUP BY pkgTracking
) AS a ON a.pkgTracking = t.pkgTracking
WHERE t.pkgStatus BETWEEN '0' AND '3';[/code]


Microsoft SQL Server MVP, MCT, MCSE, MCSA, MCP, MCITP, MCTS, MCDBA
Go to Top of Page

SergioM
Posting Yak Master

170 Posts

Posted - 2013-07-30 : 14:06:33
quote:
Originally posted by James K

This forum is for Microsoft SQL Server, so there may be very few MySQL experts here. You might get faster and more accurate answers at a MySQL forum or other generalized forums such as dbforums.com

Looking from T-SQL perspective, I don't see anything wrong with the query unless you were not joining on all columns that you should when you join the activity table.


Thanks. I've also posted it to the MySQL forum

quote:
Originally posted by Lamprey

Maybe you need to add another column to your join or that's just how the data is. Hard to tell without any knowledge of your system.

Hmm, it always seemed pushy to me to add a sql dump, but if that's the norm, I'm happy to do it. I've stripped it down to just the one tracking number & the 4 activity rows which result in the cartesian product.

http://u2xs.com/tmp/shipStatus.sql

quote:
Originally posted by SwePeso

I can't seem to get it to work in MySQL. I've removed the dbo references and changed them to MySQL friendly format, but I must be missing something.

-Sergio
Go to Top of Page
   

- Advertisement -