Re: Efficiency of Views

On 3/2/06 12:57 PM, "Matt Helm" <code(dot)name(dot)eric(at)gmail(dot)com> wrote:

> I have a table (call it T1) made up of a join from two other tables
> and a few calculated columns.
>
> Currently, T1 gets refreshed by manually calling a function that does
> the select on the join and then loops through each row doing an
> update / insert as needed.
>
> Obviously it would be nice to put this in a view so that I don't
> have to worry about someone forgetting to call the refresh function.
>
> My question (probably a common one):
>
> When I select a single row from the view using WHERE will
> the view build the calculated columns for every row regardless?

Nope. It does the right thing. Try creating the view you want and then do:

explain select .... From view where ...

Then try:

explain select ... FULL SELECT STATEMENT USED TO MAKE THE VIEW.

They will be the same, I think.

Sean