Question

I have this query which runs fine:

SELECT count(distinct p.products_id) as total 
FROM (products p 
        LEFT JOIN manufacturers m 
        USING(manufacturers_id), products_description pd, 
              categories c, products_to_categories p2c ) 
LEFT JOIN meta_tags_products_description mtpd 
          ON mtpd.products_id= p2c.products_id 
          AND mtpd.language_id = 1 
WHERE (p.products_status = 1 AND p.products_id = pd.products_id 
       AND pd.language_id = 1 AND p.products_id = p2c.products_id 
       AND p2c.categories_id = c.categories_id 
       AND (
            (pd.products_name LIKE '%3220%' 
             OR p.products_model LIKE '%3220%' 
             OR m.manufacturers_name LIKE '%3220%' 
             OR (mtpd.metatags_keywords LIKE '%3220%' 
                 AND  mtpd.metatags_keywords !='') 
             OR 
             (mtpd.metatags_description LIKE '%3220%' 
              AND   mtpd.metatags_description !='') 
             OR 
              pd.products_description LIKE '%3220%'
            ) 
           ) 
      )

But I want to either search for those WHERE clauses or, given a numeric keyword value as in the example, search for the products id by just adding this to the previous query:

 OR (p.products_id=3220)

But for some reason that addition freezes the mysql server. It just keeps executing the query and it never ends. I have to manually restart the server. What is it that I am doing wrong?

Answer 1

When you add the OR to the end (assuming you’re adding it after the last paren), you are creating a cartesian join as you’re invalidating your JOIN conditions that you placed in your WHERE clause (p.products_id = pd.products_id, p.products_id = p2c.products_id and p2c.categories_id = c.categories_id). Also, why are you putting the initial tables (products, manufacturers, products_description, categories, products_to_categories) inside of parenthesis? Instead, try something more like this:

SELECT count(distinct p.products_id) as total 
FROM products p 
LEFT JOIN manufacturers m USING(manufacturers_id)
LEFT JOIN products_description pd using products_id
LEFT JOIN categories c USING (categories_id)
LEFT JOIN products_to_categories p2c USING (products_id)
LEFT JOIN meta_tags_products_description mtpd 
          ON mtpd.products_id= p2c.products_id 
          AND mtpd.language_id = 1 
WHERE (p.products_status = 1  
       AND pd.language_id = 1  
       AND (
            (pd.products_name LIKE '%3220%' 
             OR p.products_model LIKE '%3220%' 
             OR m.manufacturers_name LIKE '%3220%' 
             OR (mtpd.metatags_keywords LIKE '%3220%' 
                 AND  mtpd.metatags_keywords !='') 
             OR 
             (mtpd.metatags_description LIKE '%3220%' 
              AND   mtpd.metatags_description !='') 
             OR 
              pd.products_description LIKE '%3220%'
            ) 
           ) 
      )
      OR (p.products_id=3220)

I do not understand what p.products_status = 1 AND pd.language_id = 1 mean in your case, so you may need to adjust how those are included in the JOIN.