excellent. useful.

Swati4/28/2008 9:26:54 PM

Exceptionally useful, even beyond Itzik's usual excellence!

Rho Trading4/7/2008 9:21:13 AM

Hi gitega,
Thanks so much for your feedback. Below is Itzik Ben-Gan's response to your questions.

“When the comparison columns are all that you need to return from a query, then yes, you can consider EXCEPT as an alternative to outer joins (or the NOT EXISTS predicate).
Just remember what I explained in the article in terms of the difference between EXCEPT and the alternatives in terms of NULL comparisons.

If you need to return also columns that you’re not comparing, a join gives you this option while a set operation doesn’t.

Cheers,
Itzik”

Please feel free to contact me if you have additional questions.

Megan Bearly
Associate Editor, SQL Server Magazine
mbearly@penton.com

meganbearly 4/7/2008 8:11:38 AM

Great article!

How would the outputs of EXCEPT statement differ from a left join when looking for rows that need to be inserted into target table ? OR Stated another way, is the EXCEPT statement an alternative to a LEFT JOIN in this use case (identify rows to insert to a target table)?

Lorrin4/4/2008 9:09:25 AM