title: MySQL group_concat_max_len in a query
body: <p>I'm searching a way to insert this </p>
  
  <p><code>SET GLOBAL group_concat_max_len=15000</code></p>
  
  <p>in an existing SQL query such as the following: </p>
  
  <pre><code>SELECT * 
  FROM `Pages` 
  WHERE id =1 
  UNION SELECT 1 , 2, IF( 1 &gt;0, SET GLOBAL group_concat_max_len=15000,'B' ) 
  </code></pre>
  
  <p>But I couldn't make it work because usually this query is executed on its own and I was wondering if some of you had any idea how to make it work</p>