NYCPHP Meetup

[Dan Cech]

Michael Southwell wrote:
> It's always seemed easier and clearer to me to use WHERE instead of JOIN
> (where the table IDs are indeed named id, and the foreign keys are
> labeled with the table name):
> 
> SELECT product_name, vendor_name
> FROM product, vendor
> WHERE vendor.id = product.vendor_id

The problem with this approach is that you end up with the join
conditions and the 'real' selection criteria mashed together.

SELECT product_name, vendor_name, category_name
FROM product, vendor, category
WHERE vendor.id = product.vendor_id AND price > 50 AND category.id =
product.category_id AND color = 'red'

vs

SELECT product_name, vendor_name, category_name
FROM product
JOIN vendor ON vendor.id = product.vendor_id
JOIN category ON category.id = product.category_id
WHERE price > 50 AND color = 'red'

I mixed up the order of the WHERE elements in the first query for the
purposes of this example, but I have seen stuff like that in production
code.

Dan