title: Searching multiple tables with Subquery
body: <p>What I need to do is searching from companies and tags table and listing companies.</p>
  
  <p>My table structure is as follows;</p>
  
  <p>tags (tag_ID, tag)
  tag_relation (tag_ID, company_ID)
  companies (company_ID, company_name, company_description)</p>
  
  <p>The query should be able to search both company info (name, description) and tags. If tag searched, related companies should return.</p>