Store calculations in a table or use computed columns?

Question

Store calculations in a table or use computed columns?

Viewing 3 posts - 1 through 4 (of 4 total)

You must be logged in to reply to this topic. Login to reply

Lowell SSC Guru Points: 323740 More actions · Answer 1

the devil is in the details, but here's my two cents:

use computed columns or a view which does the computation for you whenever possible.

i don't know if you've ever tried it, but storing a formula in a field, and then trying to execute the value of the field to get the results is a real pain in the... whatever.

try it with a simple example...

declare @MyCalculation varchar(30)

SET @MyCalculation ='SELECT 1 + 2+ 3'

EXEC (@MyCalculation)

--or worse COLUMNA + COLUMNB

see if you can get the results back...it's a pain.

Lowell

--help us help you! If you post a question, make sure you include a CREATE TABLE... statement and INSERT INTO... statement into that table to give the volunteers here representative data. with your description of the problem, we can provide a tested, verifiable solution to your question! asking the question the right way gets you a tested answer the fastest way possible!

tobbe 47526 Grasshopper Points: 18 More actions · Answer 2

Thanks Lowell, I'll start working on using computed columns.

If anyone else pictures an even better way when reading this post, please share your ideas 🙂

Jeff Moden SSC Guru Points: 1004664 More actions · Answer 3

As Yogi Bera used to say, "When you come to a fork in the road, take it.". If you can suscessfully create a computed column, try to make it a "persisted" computed column.

--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)