NYCPHP Meetup

[David Krings]

tedd wrote:
> At 9:41 AM -0400 9/1/09, Andy Dirnberger wrote:
>> On Tue, Sep 1, 2009 at 8:58 AM, tedd <tedd at sperling.com> wrote:
>>>
>>>  I need to understand joins much better than I do now because the 
>>> first query I fully understand while the second I don't.
>>>
>>
>> Think of the WHERE clause as the filter.  Use it to place restrictions
>> on what information is returned.
>>
>> WHERE price > 50 AND color = 'red'
> 
> I fully understand WHERE, it's understanding how JOIN's simplify things.
> 

Well, there are different types of joins. The Where join always gives an inner 
join - says someone who didn't really get joins either. Using the join makes 
things to be more systematic, which will help a lot when you join across a 
dozen tables and use Where filters that are based on the result of other 
queries. It might just be that we never came across such complicated queries, 
which exposed us never to any cases where using something else than the WHERE 
join would make much difference.
You may want to check out the pages about SQL join on W3C schools.

David