Mysqlphp can print a date with a ticket, but how can I display it by year?

Segmentfault. comq10... my ticket system has been able to print the date when there is a ticket, for example, 2016-06-062016-06-052016-06-032016-06-01, and can also display the total number of days {code ...} but how should I do it by year... sense of the SF master points of https://segmentfault.com/q/10...

My ticket system has been able to print a date with a ticket, for example
2016-06-06 2016-06-05 2016-06-03 2016-06-01

This format
It also shows the total number of days.

$DONE_ORDER = mysql_query("SELECT distinct buytime FROM `buy` "); while($DONE_ORDER_ROW = mysql_fetch_array($DONE_ORDER)){?>
   
  

But how can I show it by year?
For example

2016

2016-06-06 2016-06-05 2016-06-03 2016-06-01

2015

2015-04-06 2015-05-05 2015-03-03 2015-07-01

Reply content:

Sense of the SF master points of https://segmentfault.com/q/10...

My ticket system has been able to print a date with a ticket, for example
2016-06-06 2016-06-05 2016-06-03 2016-06-01

This format
It also shows the total number of days.

$DONE_ORDER = mysql_query("SELECT distinct buytime FROM `buy` "); while($DONE_ORDER_ROW = mysql_fetch_array($DONE_ORDER)){?>
   
  

But how can I show it by year?
For example

2016

2016-06-06 2016-06-05 2016-06-03 2016-06-01

2015

2015-04-06 2015-05-05 2015-03-03 2015-07-01