[thelist] Tip: Double aliasing tables in MySQL
Frank
lists at frankmarion.com
Mon Aug 18 02:38:01 CDT 2003
<tip type="MySQL" author="Frank Marion">
Did you know that you can alias a table more than once in the same query?*
I had to edit some of my first work, done years ago to handle changes to a
database and I discovered that a table can be aliased more than once with
apparently little or no penalty in speed or robustness.
SELECT
p.ProductID
, p.ProductName
, p.BrandID
, p.CategoryID
, b.cat_id AS BrandID
, b.cat_name AS BrandName
, c.cat_id
, c.cat_name
FROM Products p
LEFT JOIN categories b
ON p.BrandID = b.cat_id
LEFT JOIN categories c
ON p.CategoryID = c.cat_id
WHERE [... and so on and so forth ...]
This was a quick and easy fix to my problem, saving me a couple of hours of
tedious search and replace.
*I can only attest that this works in MySQL 4.x
</tip>
* And I get the feeling that Rudy is going to jump all over my butt over this.
--
Frank Marion lists at frankmarion.com Keep the signal high.
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