title: PowerBuilder NULL and Empty variable
body: <p>I'm using PowerBuilder and have a problem with the if condition. I want to check if a variable is not null or it is not empty. </p>
  
  <p>So first I have following if condition to test if the variable is null or not:</p>
  
  <pre><code>IF IsNull(ls_name) THEN
      messagebox("ls_name", "is null")  //true
  else
      messagebox("ls_name", "is not null")
  end if
  </code></pre>
  
  <p>From the above condition, I know that ls_name is null. Now I test if its empty or not:</p>
  
  <pre><code>if ls_name = "" then
      messagebox ("ls_name", "is empty")
  else
      messagebox("ls_name", "is not empty") //true
  end if
  </code></pre>
  
  <p>And i get that ls_name is not empty.</p>
  
  <p>Now when I use an if condition to check if ls_name is NOT Null or it is NOT empty, I put the following if condition:</p>
  
  <pre><code>IF not IsNull(ls_name) or ls_name &lt;&gt; "" THEN
      messagebox("test", "condition true")
  else
      messagebox("test", "condition false")  //this becomes true.
  end if
  </code></pre>
  
  <p>It goes to the else part of the condition. Shouldn't the if part become true? Am I writing the if condition wrong? </p>