title: how group_concat with like where condition in that case
body: <p>I have tables(mysql 5.5 INNODB):sample small data + cut not relevant columns for questions - real data huge(more then 10,000,000 rows in meeting table) </p>
  
  <p><strong>INPUT:</strong></p>
  
  <pre><code>day:
  
  day_id(primary key)|sunday|monday|tuesday|wensday|thursday|friday|saturday
  ---------------------------------------------------------------------------
  60                 |1     |1     |1      |1      |1       |1    |1
  74                 |0     |1     |0      |0      |0       |0     |0
  98                 |0     |0     |0      |0      |0       |0     |0
  ..etc......................................................................
  
  meeting:
  
  day_id(foreign key)|time    |type
  ----------------------------------
  60                 |20:09:00|1
  98                 |07:00:00|1
  74                 |22:01:00|4
  98                 |10:00:00|1
  60                 |23:09:00|2
  98                 |06:00:00|2
  74                 |21:04:00|6
  98                 |08:00:00|6
  .....etc.....................
  </code></pre>
  
  <p><strong>OUTPUT:</strong></p>
  
  <pre><code>sunday_times          |monday_times                           |....etc
  -------------------------------------------------------------------------------------------------
  20:09:00,etc...       | 20:09:00,etc..   |
  ................etc..............................................................................
  </code></pre>
  
  <p>I think something like that (but I am new  with sql soo i don't know if it good or legal)</p>
  
  <pre><code> SELECT 
     GROUP_CONCAT(time where day.sunday=1 ORDER BY time) as sunday_times, 
     GROUP_CONCAT(time where day.monday=1 ORDER BY time) as monday_times,  
     etc..
   FROM day
   JOIN meeting ON meeting.day_id=day.day_id
   GROUP BY type
  </code></pre>