title: MySQL UNION not working for where condition
body: <p>I wanted to show all result whose <code>post_status</code> is <code>0</code> but its not working. Its showing result even if the <code>post_status</code> is not <code>0</code>. I have `post_status' in both table.</p>
  
  <h2>MySQL query</h2>
  
  <pre><code>SELECT `id`, 
         `brand_category`, 
         `model_category`, 
         `titles`, 
         `images`, 
         `ads_main_pic`, 
         `post_status` 
  FROM   post_ads 
  WHERE  post_status = 0 
         AND `titles` LIKE '%de%' 
          OR `brand_category` LIKE '%de%' 
          OR `model_category` LIKE '%de%' 
  UNION 
  SELECT `id`, 
         `company` AS brand_category, 
         `keyword` AS model_category, 
         `title`   AS titles, 
         NULL      AS images, 
         NULL      AS ads_main_pic, 
         `post_status` 
  FROM   job 
  WHERE  post_status = 0 
         AND `title` LIKE '%de%' 
          OR `keyword` LIKE '%de%' 
          OR `company` LIKE '%de%' 
  </code></pre>