Mysql SQL statement per half hour average calculation _mysql

Table structure:

CREATE TABLE ' instance ' (
 ' id ' int (one) unsigned not null auto_increment,
 ' timestamp ' int (a) unsigned DEFAULT null ,
 ' CPU ' decimal (8,3) DEFAULT NULL,
 PRIMARY KEY (' id ')
) Engine=innodb;

Statistics are averaged every half hour, and implementations can be as follows:

Select ' Timestamp '-' timestamp '% (5*60), AVG (CUP) from
' instance '

In addition, there are:

SELECT queuename, HOUR (DT) as H, FLOOR (MINUTE (DT)/m) as V, 
   avg (memoryused), sum (memoryused), COUNT (memoryused) 
  from queue_resource 
where dt>= ' 2014-04-14 00:00:00 ' 
GROUP by H, V, QueueName;