title: How to tell the logic like plus sign with OR in solr
body: <p>All:</p>
  
  <p>Right now, I want to input a search in SOLR like this:</p>
  
  <pre><code>+keyword1 OR +keyword2
  +keyword1 OR keyword2
  </code></pre>
  
  <p>Could anyone explain how SOLR process this logic?
  I am not sure if this above eaquals </p>
  
  <pre><code>keyword1 AND keyword2
  keyword1
  </code></pre>
  
  <p>Thanks</p>