title: Replace repetitive values with Null in MySQL query response
body: <p>I have two tables in my MySQL Server database with a common column:</p>
  
  <p><strong>Table1</strong></p>
  
  <pre><code>+---------------------------------+
  | columnA       | columnB         |
  +---------------------------------+
  |  123          |  lorem          |
  |  456          |  ipsum          | 
  |  456          |  dolor          |
  +---------------------------------+
  </code></pre>
  
  <p><strong>Table2</strong></p>
  
  <pre><code>+---------------------------------+
  | columnA       | columnC         |
  +---------------------------------+
  |  123          |  sit            |
  |  123          |  amet           | 
  |  123          |  consectetur    | 
  |  456          |  adipiscing     |
  +---------------------------------+
  </code></pre>
  
  <p>I want to get all values of <code>columnB</code> and <code>columnC</code> where <code>columnA</code> is <code>123</code>. The query I'm using is:</p>
  
  <pre><code>SELECT Table1.columnB, Table2.columnC
  FROM Table1
  INNER JOIN Table2 ON Table1.columnA = Table2.columnA
  WHERE Table1.columnA = '123';
  </code></pre>
  
  <p>Here's the <strong>query result</strong>:</p>
  
  <pre><code>+---------------------------------+
  | columnB       | columnC         |
  +---------------------------------+
  |  lorem        |  sit            |
  |  lorem        |  amet           | 
  |  lorem        |  consectetur    | 
  +---------------------------------+
  </code></pre>
  
  <p>I'm getting the required results but i don't want these repetitive values as in <code>columnB</code> in this example. Is there any way to replace (last two) redundant values <code>lorem</code> with either <code>NULL</code> or whitespace? Something like:</p>
  
  <pre><code>+---------------------------------+
  | columnB       | columnC         |
  +---------------------------------+
  |  lorem        |  sit            |
  |               |  amet           | 
  |               |  consectetur    | 
  +---------------------------------+
  </code></pre>