Conditional field in mysql join query result

Question

I have following two tables

1. publisher_site_regionwise_adratio
publisher_id | site    | region | ad_ratio | product_code
=========================================================
001          | xyz.com | US     | 8:2      | TB

and

2. publisher_site_regionwise_info
publisher_id | site    | region | regional_keywords
=======================================================
001          | xyz.com | US     | business, warehouse

Now second table has data that is not product_code wise. Regional info for sites is irrespective of product_code for a publisher with a particular site for a particular region. Now I want a query that will give me following fields

site    | region | ad_ratio | has_regional_info
============================================
xyz.com | US     | 8:2      | 1

has_regional_info column will have 0 or 1 depending upon whether a site in a particular region has regional_keywords mapped or not.

I can't possibly imagine how I can use JOIN and get such result. Any help will be very appreciated.

Answer 1

I would take a simple JOIN into your info table, then check if there is data in the regional_keywords column to determine your 1 or 0 for has_regional_info

SELECT ar.site, ar.region, ar.ad_ratio
   , CASE
        WHEN i.regional_keywords IS NOT NULL THEN 1
        ELSE 0
     END AS has_regional_info
FROM publisher_site_regionwise_adratio AS ar
LEFT JOIN publisher_site_regionwise_info AS i ON ar.publisherId = i.publisherId

If your foreign key between publisher_site_regionwise_adratio and publisher_site_regionwise_info is more than just publisherId (difficult to tell with 3 repeated columns in your example) then just add these to the ON statement of the join like: AND ar.otherColumn = i.otherColumn

Answer 2

SELECT ratio.site, ratio.region, ratio.ad_ration,
    IF(info.has_regional_info IS NULL, true, false)
FROM publisher_site_regionwise_adratio AS ratio
LEFT JOIN publisher_site_regionwise_info AS info
    ON ratio.publisher_id = info.publisher_id

Answer 3

select publisher_site_regionwise_adratio.site,  
       publisher_site_regionwise_adratio.region,
       publisher_site_regionwise_adratio.ad_ratio,
       LENGTH(regional_keywords)>0 as has_regional_info
          from publisher_site_regionwise_adratio 
            join publisher_site_regionwise_info.publisher_id 
              on publisher_site_regionwise_adratio.publisher_id 
                 = publisher_site_regionwise_info.publisher_id

Answer 4

This should do:

SELECT a.publisher_id, a.site, a.ad_ratio,
    i.regional_keywords IS NOT NULL AS has_regional_keywords
FROM publisher_site_regionwise_adratio a, publisher_site_regionwise_info i
WHERE a.publisher_id = i.publisher_id;