Computed Columns - Part 2

Computed columns are an interesting alternative to expressions in a stand alone select or a select contained in a view. Not something you'll use often, but good to know how it works.

Andy Warren is a software trainer focusing on SQL Server, a member of the PASS Board of Directors, and a principal in this site - SQLShare.com.

Satyabodhi Densmore on 10/8/2009

Mention problems with BCP

Travis on 10/9/2009

It would have been nice if you have also discussed the IsPersisted property associated with computed columns...

Preethi on 10/9/2009

Good.

yashpal on 10/10/2009

good work, I wasnt know sql server provides calculated columns

Lloyd Edwards on 10/11/2009

none

13C5A7DDEE on 10/19/2009

Very good

Rob Wingate on 10/21/2009

Andy is great.

Tim McMurdo on 1/7/2010

falling in love with this site !!! 2 thumbs up !

John Langston on 3/17/2010

Good tip

ricardoacaraujo@hotmail.com on 3/24/2010

RAzoavel

Prathap on 10/10/2010

Good video

Roxanne Lenahan on 10/29/2010

Very quiet and hard to hear.

FELIX on 11/2/2010

Excellent video

nilesh bilimoria on 11/17/2010

nice job

Peter Voutov on 12/6/2010

You may have mentioned "Is Persisted" property as way to "realize" columns. This may be useful in large tables involving complex calculations of computed columns that you may not want to perform on the fly. Strangely enough, creating an index doesn't toggle the "Is Persisted" flag, which I expected it do... At least the documentation seems to require it. http://msdn.microsoft.com/en-us/library/ms189292.aspx#BKMK_persisted

Edward on 2/2/2011

thanks.

Sateesh on 2/23/2012

Good One

G Bryant McClellan on 2/23/2012

I think it would have been useful to show how the second computed column index might be expanded with an included column for the email address. That would keep the resultant search from being so narrow and unrealistic as well as showing the additional flexibility one could gaine with computed columns optimally indexed.

Christian Bahnsen on 2/23/2012

Andy, if you make the calculation persistent(using the Is Persisted property) can/do you eliminate the some or all of the overhead related to searching on the column?

Richard Scott on 2/23/2012

This presenter is very easy to understand amongst those I have watched and is very concise as to the code and business reason where his presentations could apply.

mark on 2/24/2012

nice

Josh on 2/24/2012

Very good, liked that you went into details on performance problems, gave an example of why you would use it, etc...

56ECAFD1F1 on 2/25/2012

Didn't mention the added cost during inserts and updates.

Dan on 2/27/2012

Excellent across the board! Thank you very much!

Cheryl on 2/28/2012

I guess good to know, but goes against everything I’ve ever been taught. If I have two columns, why would I create a column in the table to concatenate them when I could do it in the query, report, etc. Just seems like a waste of space to me.

Steve Duck on 3/27/2012

Seemed like a tad bit too much to cover in this mini segment, but well done nonetheless. I liked how the performance was explained.