How to LEFT JOIN a SubQuery?

[resting]

What I'm doing here is to add a column (named outOfStock) to my existing table prod_info.

I used this query to generate my outOfStock table.

SELECT prod_id, XS, S, Splus, M, L, XL FROM prod_info AS outOfStock WHERE
     XS    IS NULL &&
     S     IS NULL &&
     Splus IS NULL &&
     M     IS NULL &&
     L     IS NULL &&
     XL    IS NULL 

Then I used a LEFT JOIN to combine them.

SELECT * FROM prod_info LEFT JOIN (
  SELECT prod_id, XS, S, Splus, M, L, XL FROM prod_info AS outOfStock WHERE
     XS    IS NULL &&
     S     IS NULL &&
     Splus IS NULL &&
     M     IS NULL &&
     L     IS NULL &&
     XL    IS NULL
) ON prod_info.prod_id = outOfStock.prod_id 

It prompts me this error message:

Every derived table must have its own alias.

I'm totally a goner at subqueries and joins. How does it mean and how do I achieve what I want?

Oh yes, please recommend some really simple reading on joins and subqueries. Most that I'd seen are quite difficult to understand.

[resting]

Ok, I'd got it to work with this:

SELECT * FROM prod_info LEFT JOIN (
  SELECT prod_id, XS, S, Splus, M, L, XL FROM prod_info AS outOfStock WHERE
     XS    IS NULL &&
     S     IS NULL &&
     Splus IS NULL &&
     M     IS NULL &&
     L     IS NULL &&
     XL    IS NULL
) AS outOfStock ON prod_info.prod_id = outOfStock.prod_id 

But its not what I wanted.

How do I sort of create a new column and add it to my existing table?

Basically I want to find all products that are out of stock.
Store them in a column named outOfStock.
And add it to my exisiting prod_info table.

outOfStock column will contain the prod_id of those products which have nulls in XS, S, Splus, M, L, XL.

[resting]

oh yes..i found the answer. Had the subquery wrong in the 1st place.

SELECT * FROM prod_info LEFT JOIN (
  SELECT prod_id as outOfStock FROM prod_info WHERE
     XS    IS NULL &&
     S     IS NULL &&
     Splus IS NULL &&
     M     IS NULL &&
     L     IS NULL &&
     XL    IS NULL
) AS outOfStock ON prod_info.prod_id = outOfStock.outOfStock 

[guido2004]

SELECT 
    prod_info.*
  , prod_id AS outOfStock 
FROM prod_info 
WHERE XS    IS NULL 
AND   S     IS NULL 
AND   Splus IS NULL 
AND   M     IS NULL 
AND   L     IS NULL 
AND   XL    IS NULL

[resting]

SELECT 
    prod_info.*
  , prod_id AS outOfStock 
FROM prod_info 
WHERE XS    IS NULL 
AND   S     IS NULL 
AND   Splus IS NULL 
AND   M     IS NULL 
AND   L     IS NULL 
AND   XL    IS NULL

wow...thats nice. thanks!