QUery

For retreiving a particular result I can write a query in this way-
Select t1.person_id,t2.age from table1 t1,table2 t2
where t1.person_id=t2.person_id

Or
I can write the same query in a different manner like this-
Select t1.person_id,t2.age from table1 t1
inner join table2 t2
on t1.person_id=t2.person_id

I want to know is there any particular effect between these two processes?Which one is supposed to follow?

SubhasishThere is no difference in effects for the both, but the 'inner join' statement complies with the latest ANSI standard and the other one is the old way.|||The second version is the ANSI way of writing a join. It's also far easier to understand IMHO.

To make that query even simpler to follow, you could use a USING clause:

SELECT
t1.person_id
, t2.age
FROM
table1 t1
INNER JOIN
table2 t2
USING ( person_id )

Have a look at this ANSI join article at Database Journal (http://www.databasejournal.com/features/oracle/article.php/2209301).

Hope this helps,

Matt. :)|||subhasishray,

the reason it make no difference for a simple query such as yours is because MSSQL Server will change WHERE logic to JOIN logic prior to processing whenever possible. For complex queries the optimizer may not be able to do this, and the WHERE logic can affect performance.

use JOIN logic whenever you can. it logically separates table linking from query criteria and filters.

blindman