title: SELECT statement with where clause IN is not reading variable in MySQL
body: <p>I'm running SELECT statement (database MySQL version 5.5.27 under Windows 7) with variable in WHERE clause. It supposed to return 6 records, but it doesn't. Below is a simple test code.</p>
  
  <pre><code>-- Test-I
  SET @group_saids := (SELECT REPLACE(
                                      '''ClicPlan - España|ClicPlan - Francia|ClicPlan - UK|ClicPlan - Belgique|ClicPlan - Argentina|Clicplan - Turkey'''
                                      ,'|',"','") as aids_list from dual);
  
  select @group_saids from dual;
  
  
  select sd.aid
  FROM said_aid sd
  where sd.said in (@group_saids);
  </code></pre>
  
  <p>-- No records selected;</p>
  
  <p>-- Test-II</p>
  
  <pre><code>select sd.aid
  FROM said_aid sd
  where sd.said in ('ClicPlan - España','ClicPlan - Francia','ClicPlan - UK',
                    'ClicPlan - Belgique','ClicPlan - Argentina',
                    'Clicplan - Turkey');
  
  aid
  ----
  3045
  3253
  3254
  3260
  3268
  3270
  </code></pre>
  
  <p>In the code above Test-I, select from table said_aid doesn't return records, but should be 6 records output.
  Int the Test-II same query with hard coded IN values return 6 records output.
  No ERRORS during execution.</p>