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 
         


        

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

Answer 2

I don't think you can use your "width" alias in your "width between .. and .."; you need to repeat the raw calculation, sadly. Same for "height". So, the following should work:

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      (((SUM(c.width_feet)*12)+(SUM(c.width_inches))) BETWEEN '0' AND '275') 
AND      (((SUM(c.height_feet)*12)+(SUM(c.height_inches))) BETWEEN '0' AND '599') 
ORDER BY c.item_no 

Answer 3

You can use aliases in the order by clause, but you can't use aliases in the where or group by clause. Either you repeat the expression or you can use a subquery.