Combine 2 MySQL queries to improve performance

Question

I have the following 2 queries. The first is finding some product_id s based on some joins. It's running fast.

SELECT Group_concat(DISTINCT( p.products_id )) AS comma_separated 
FROM   products p 
       left join specials s 
              ON p.products_id = s.products_id 
       left join products_to_categories p2c 
              ON p.products_id = p2c.products_id 
       left join products_description pd 
              ON p.products_id = pd.products_id 
       inner join products_attributes pa 
               ON p.products_id = pa.products_id 
WHERE  p.products_status = '1' 
       AND Date_sub(Curdate(), interval 7000 day) <= p.products_date_added 
ORDER  BY p.products_id DESC

After that, the following query is executed and use all the products_id s found in the first query:

SELECT DISTINCT pov.products_options_values_id, 
                pov.products_options_values_name, 
                pa.options_values_price, 
                pa.price_prefix 
FROM   products_attributes pa, 
       products_options_values pov 
WHERE  Find_in_set(pa.products_id, 
'**Long list of comma separated products_ids found in the first query**') 
AND pa.options_id = 1 
AND pa.options_values_id = pov.products_options_values_id 
AND pov.language_id = '1' 
GROUP  BY pov.products_options_values_id 
ORDER  BY pov.products_options_values_sort_order ASC

The list of products_id s in the Find_in_set clause is very long and making this query take quite a long time to execute.

Is there any way of using joins or other way to rewrite the second query or combine both to improve performance?

Answer 1

Try something like this

SELECT DISTINCT pov.products_options_values_id, 
                pov.products_options_values_name, 
                pa.options_values_price, 
                pa.price_prefix 
FROM   products_attributes pa, 
       products_options_values pov,
       (SELECT p.products_id
            FROM   products p 
                   left join specials s 
                          ON p.products_id = s.products_id 
                   left join products_to_categories p2c 
                          ON p.products_id = p2c.products_id 
                   left join products_description pd 
                          ON p.products_id = pd.products_id 
                   inner join products_attributes pa 
                           ON p.products_id = pa.products_id 
            WHERE  p.products_status = '1' 
                   AND Date_sub(Curdate(), interval 7000 day) <= p.products_date_added 
            GROUP BY p.products_id
        ) t
WHERE t.products_id = pa.products_id
AND pa.options_id = 1 
AND pa.options_values_id = pov.products_options_values_id 
AND pov.language_id = '1' 
GROUP  BY pov.products_options_values_id 
ORDER  BY pov.products_options_values_sort_order ASC