title: Set value to empty string (case statement)
body: <p>In my stored procedure, I have a case condition in my select statement. </p>
  
  <p>Like this:</p>
  
  <pre><code>select Distinct col_1, col_2, col_3, Case when (ISNULL(char_01, 'M') = 'M') 
  Then
  .....
  Else
  End
  
  From my_table
  </code></pre>
  
  <p>You can see that I have a column name <code>char_01</code>. Let say I want to replace <code>char_01</code> to 'M' then there is a <code>null</code> column. Also I want to replace <code>char_01</code> to 'M' when there is an <strong>empty column</strong> . So far I can only check the <code>null</code> column <code>(ISNULL(char_01, 'M') = 'M')</code> but I am not sure how to also check empty column. </p>
  
  <p>I have tried:</p>
  
  <pre><code>Case when (ISNULL (char_01, 'M') = 'M') or //If char_01 is empty, then replace this column as 'M'
  THen .... 
  Else
  end
  </code></pre>
  
  <p>I am stuck at the second part, any help will be appreciated. Thanks </p>