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Optimized way to write

Author

Topic

sent_sara
Constraint Violating Yak Guru

377 Posts

Posted - 2013-06-18 : 14:10:34

Can i know how to write the optimized way in select statement,avoiding the case statment.


select 
CASE WHEN RACCT = '' OR RACCT IS NULL THEN 'No_Account' 
ELSE 'AC_' + RACCT + '' END  AS Account
From DBO.GL

visakh16
Very Important crosS Applying yaK Herder

52326 Posts

Posted - 2013-06-18 : 14:14:23

it can be simplified as below but internally its equivalent to CASE ...WHEN so cant say its optimized in performance


select COALESCE('AC_' + NULLIF(RACCT,'') + '','No_Account')  AS Account
From DBO.GL

------------------------------------------------------------------------------------------------------
SQL Server MVP
http://visakhm.blogspot.com/
https://www.facebook.com/VmBlogs

James K
Master Smack Fu Yak Hacker

3873 Posts

Posted - 2013-06-18 : 15:49:02

When you run a query, most of the resources are spent on retrieving the data, sorting it etc. Very little resources are required for arithmetic/logical operations as in the CASE expression you are using. So I would keep it as it is. It is more readable as well, just format it nicely

SELECT  
    CASE 
       WHEN RACCT = '' OR RACCT IS NULL THEN 'No_Account'
       ELSE 'AC_' + RACCT + ''
    END AS Account
FROM
    BO.GL

nevzab
Starting Member

34 Posts

Posted - 2013-06-18 : 16:33:14

Is this any better?

select

CASE WHEN isnull(RACCT,'') = '' THEN 'No_Account'
ELSE 'AC_' + RACCT + '' END AS Account
From DBO.GL

sent_sara
Constraint Violating Yak Guru

377 Posts

Posted - 2013-06-18 : 17:22:59

Thanks everyone. i've implemented all the changes mentioned.but
performance wise no variance.Thanks anyway

quote:
Originally posted by nevzab

Is this any better?

select

CASE WHEN isnull(RACCT,'') = '' THEN 'No_Account'
ELSE 'AC_' + RACCT + '' END AS Account
From DBO.GL

visakh16
Very Important crosS Applying yaK Herder

52326 Posts

Posted - 2013-06-19 : 01:01:40

quote:
Originally posted by nevzab

Is this any better?

select

CASE WHEN isnull(RACCT,'') = '' THEN 'No_Account'
ELSE 'AC_' + RACCT + '' END AS Account
From DBO.GL

still the same other than a small overhead may be due to use of function

------------------------------------------------------------------------------------------------------
SQL Server MVP
http://visakhm.blogspot.com/
https://www.facebook.com/VmBlogs

sent_sara
Constraint Violating Yak Guru

377 Posts

Posted - 2013-06-19 : 01:15:36

hi visakh,
I need one more help.
can you have a look on the topic "query tuning"

quote:
Originally posted by visakh16

quote:
Originally posted by nevzab

Is this any better?

select

CASE WHEN isnull(RACCT,'') = '' THEN 'No_Account'
ELSE 'AC_' + RACCT + '' END AS Account
From DBO.GL

still the same other than a small overhead may be due to use of function

------------------------------------------------------------------------------------------------------
SQL Server MVP
http://visakhm.blogspot.com/
https://www.facebook.com/VmBlogs

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