SharkD wrote:
> There are three types of joins. 

There's one kind of join in relational theory. There are three or four kinds 
of joins in SQL, each of which is a join followed by a select.

I.e., inner join isn't like an intersection. It's a cartesian join, followed 
by a select where the key from the first table matches the key from the 
second table in the result.

Outer joins are peversities caused by people not normalizing columns that 
can have NULL in them. If none of your tables can have a NULL, you never 
need an outer join.

If it was an intersection, you'd never get any rows, because you wouldn't 
have two tables with identical rows in them.

-- 
   Darren New, San Diego CA, USA (PST)
   I ordered stamps from Zazzle that read "Place Stamp Here".

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