title: IN SQL operator
body: <p>How can I modify this query? </p>
  
  <pre><code>SELECT column_a,  
    ( SELECT GROUP_CONCAT(column_b) 
      FROM table_b 
      WHERE column_b IN (main_tbl.column_a) ) AS alias_a   
  FROM table_a main_tbl
  </code></pre>
  
  <p>Assuming that column_a has a value of 1,2,3.</p>
  
  <p>The output of the above query is similar to this:</p>
  
  <pre><code>SELECT column_a,  
    ( SELECT GROUP_CONCAT(column_b) 
      FROM table_b 
      WHERE column_b IN ('1,2,3') ) AS alias_a   
  FROM table_a main_tbl
  </code></pre>
  
  <p>What I need is:</p>
  
  <pre><code>SELECT column_a,  
    ( SELECT GROUP_CONCAT(column_b) 
      FROM table_b 
      WHERE column_b IN (1,2,3) ) AS alias_a   
  FROM table_a main_tbl
  </code></pre>