title: SQL not fetching empty columns
body: <p>i have a table that looks like this</p>
  
  <pre><code>students
  ----------
  ID  | Name  | Class  | Pass
  01  | Lisa  | 01     | 1D345
  02  | Mike  | 03     | 22341
  03  | Kim   | 03     | 
  04  | Lance | 04     | 193CC
  </code></pre>
  
  <p>So I wanted to select those where Pass is not  empty, and I've tried</p>
  
  <p>SELECT * FROM students WHERE Pass IS NOT NULL;</p>
  
  <p>which returned the same table where it should have fetched me this</p>
  
  <pre><code>students
  ----------
  ID  | Name  | Class  | Pass
  01  | Lisa  | 01     | 1D345
  02  | Mike  | 03     | 22341
  04  | Lance | 04     | 193CC
  </code></pre>
  
  <p>I've also tried </p>
  
  <p>SELECT * FROM students WHERE Pass IS NOT ''; </p>
  
  <p>and </p>
  
  <p>SELECT * FROM students WHERE Pass !=''; </p>
  
  <p>both returning #1064 error, so what is the statement I should be using the fetch the required table? </p>