Re: Learning to rephrase equivalent queries?

Hi,

On 11 November 2011 00:04, Jay Levitt <jay(dot)levitt(at)gmail(dot)com> wrote:
> Sometimes the planner can't find the most efficient way to execute your
> query. Thanks to relational algebra, there may be other, logically
> equivalent queries that it DOES know how to optimize.
>
> But I don't know relational algebra.  yet.  (Date/Codd is a sleeping pill.)
> I need more experience first.
>
> Are there blogs, guides, rules of thumb, common refactoring patterns out
> there somewhere?  I'm looking for a list of basic equalities, the SQL
> equivalent of:

Have a look here: http://en.wikipedia.org/wiki/Relational_algebra
plus "External links" section

--
Ondrej Ivanic
(ondrej(dot)ivanic(at)gmail(dot)com)