Unknown column issue with mysql alias

Question

I can't figure out why i am getting an unknown column when the column is an alias that was created. Any help would be great.

code:

SELECT DISTINCT 
    c.id, 
    ((SUM(c.width_feet)*12)+(SUM(c.width_inches))) AS width, 
    ((SUM(c.height_feet)*12)+(SUM(c.height_inches))) AS height 
    FROM carpets AS c 
    WHERE c.active = '1' 
    AND (width BETWEEN '0' AND '275') 
    AND (height BETWEEN '0' AND '599') 
    ORDER BY c.item_no 

error:

Unknown column 'width' in 'where clause'

Answer 1

You cannot access the alias directly by name.

One solution is to wrap the query with the aliases in a subquery, and then refer to the alias names in an outer query:

SELECT DISTINCT * 
FROM 
    (
     SELECT c.id, 
          ((SUM(c.width_feet)*12)+(SUM(c.width_inches))) AS width, 
          ((SUM(c.height_feet)*12)+(SUM(c.height_inches))) AS height
     FROM carpets AS c 
     WHERE c.active = '1'
    ) sub
WHERE (sub.width BETWEEN '0' AND '275') 
AND   (sub.height BETWEEN '0' AND '599') 
ORDER BY sub.item_no