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[Morgan Craft]

If you are using DISTINCT probably means you need to normalize your data 
and look to join more appropriately.  Also for creating indexes you 
really need to consider how you plan to access your data and how it will 
be used - which goes back to properly normalizing database tables.  With 
properly structured tables you should be easily able to identify certain 
relationships and know where to put indexes - preferably columns that 
are used for JOINS and WHERE.

Good place to start:

http://dev.mysql.com/tech-resources/articles/intro-to-normalization.html

Hope it helps

David Krings wrote:
> Adrian Noland wrote:
>  > When it comes to choosing which columns to index, you want to pick
>> something with a high cardinality, or, for lack of a better term, 
>> "uniqueablity". Gender wont have a high cardinality because there are 
>> only 2 choices for many records. Last name on your personal family 
>> address book will have a low cardinality because of family members 
>> sharing last name. A key of last name + first name will have a high 
>> cardinality and will make a good index.
>
> Thanks for the explanation. I will index based on that. I decided to 
> go with the temp table approach for now as this lets me work with 
> queries that I can comprehend.
> I a past post I wrote that I merge the arrays that I get for each 
> table. While I in fact did that, I really need to do an intersect to 
> create an INNER JOIN. I filter each table based on the contents or 
> ranges of particular fields and only those items that have at least 
> one row in each table are the ones that I want. Two tables can have 
> only one row per item by design, so the distinct will come into play 
> for only one query. With that I also do not need an array_unique as 
> the intersect cannot have duplicate values.
>
> Good stuff!
>
> David
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