Cursor

I have to perform a number of calculations on a table but these
calculations need intermediate values ( like for example I have to
first calculate one value before I can use it in the next step of the
calcualtion). There are two ways of doing this:
1. Have columns for intermediate values ( it is possible as my
calculations are on a temp tbl) and use update statements. One update
statement for every step in the calculation.
2. Have a cursor, loop through the resultset and do the calculations
like we would in a programming language like C#.
Which one is better? Are updates ( a number of them) faster than a
cursor?
Thanks.John
A set based solution is much faster that cursors, however since you have
not posted DDL+ sample data it is hard to suggest something
"John Smith" <postmaster@.sumanthcp.plus.com> wrote in message
news:1139492787.074798.293960@.g14g2000cwa.googlegroups.com...
> I have to perform a number of calculations on a table but these
> calculations need intermediate values ( like for example I have to
> first calculate one value before I can use it in the next step of the
> calcualtion). There are two ways of doing this:
>
> 1. Have columns for intermediate values ( it is possible as my
> calculations are on a temp tbl) and use update statements. One update
> statement for every step in the calculation.
>
> 2. Have a cursor, loop through the resultset and do the calculations
> like we would in a programming language like C#.
>
> Which one is better? Are updates ( a number of them) faster than a
> cursor?
>
> Thanks.
>|||Cursors are usually slower than an SQL operation which updates all the rows
in
one go.
I would only use a cursor for this sort of operation if there were any
locking issues.
Are Riksaasen
"John Smith" wrote:

> I have to perform a number of calculations on a table but these
> calculations need intermediate values ( like for example I have to
> first calculate one value before I can use it in the next step of the
> calcualtion). There are two ways of doing this:
>
> 1. Have columns for intermediate values ( it is possible as my
> calculations are on a temp tbl) and use update statements. One update
> statement for every step in the calculation.
>
> 2. Have a cursor, loop through the resultset and do the calculations
> like we would in a programming language like C#.
>
> Which one is better? Are updates ( a number of them) faster than a
> cursor?
>
> Thanks.
>|||John Smith wrote:
> I have to perform a number of calculations on a table but these
> calculations need intermediate values ( like for example I have to
> first calculate one value before I can use it in the next step of the
> calcualtion). There are two ways of doing this:
>
> 1. Have columns for intermediate values ( it is possible as my
> calculations are on a temp tbl) and use update statements. One update
> statement for every step in the calculation.
>
> 2. Have a cursor, loop through the resultset and do the calculations
> like we would in a programming language like C#.
>
> Which one is better? Are updates ( a number of them) faster than a
> cursor?
>
> Thanks.
Neither of the above if you can avoid them. Create derived columns in
your queries or updates rather than using temp tables. Cursors are the
method of last resort for anything in SQL.
David Portas, SQL Server MVP
Whenever possible please post enough code to reproduce your problem.
Including CREATE TABLE and INSERT statements usually helps.
State what version of SQL Server you are using and specify the content
of any error messages.
SQL Server Books Online:
http://msdn2.microsoft.com/library/ms130214(en-US,SQL.90).aspx
--