How can I fix this mysql query?

I have a query as follows:

SELECT  website_url, 
        website_id, 
        website_shady, 
       (sum(dstats_hits)+website_in_ballast) as total_in, 
       (sum(dstats_hits_out)+website_out_ballast) as total_out, 
        sum(dstats_hits_out_paid) as total_paid, 
        website_in_ballast, 
        website_out_ballast 
FROM websites 
LEFT JOIN domain_stats 
          ON (
               websites.website_id = domain_stats.dstats_domid 
               AND dstats_date >= '$ratio_start'
             ) 
WHERE website_userid = $id
GROUP BY website_url 
ORDER BY website_url

The problem is with the total_in and total_out aliases. If the sum(dstats_hits) doesn't have anything to sum (because there are no records in the domain_stats table), it will not add the website_in_ballast value, and the alias returns blank, even though website_in_ballast has a value (which is a float). If there are records to sum, it functions perfectly.

I could solve this by adding the alias in php to the sum value (which could and could not be 0), but in another example I cannot do that, so Im looking for a mysql only solution.

From stackoverflow

• Maybe try to reverse it, so that you have

  website_in_ballast + sum(dstats_hits)
  

  Yegor : Nope, thats a no go.

  Sebastian Hoitz : It was just a wild guess. Then try using ysth's solution. I was thinking about that one too.

• coalesce(sum(dstats_hits),0) + ...
  

• Can you use COALESCE() to fix the null sum?

  SELECT website_url, website_id, website_shady,
         COALESCE(sum(dstats_hits), 0) + website_in_ballast as total_in,
         COALESCE(sum(dstats_hits_out), 0) + website_out_ballast as total_out,
         sum(dstats_hits_out_paid) as total_paid,
         website_in_ballast, website_out_ballast 
    FROM websites LEFT JOIN domain_stats
            ON (websites.website_id = domain_stats.dstats_domid AND
                dstats_date >= '$ratio_start') 
    WHERE website_userid = $id
    GROUP BY website_url 
    ORDER BY website_url;
  

  Untested SQL!

  jishi : COALESCE is a standard way of handling alternative values to NULL, however MySQL has it's proprietary IFNULL() aswell.