mysql连续聚合原理与用法实例分析

CREATE TABLE EmpOrders (
empid INT NOT NULL,
ordermonth DATE NOT NULL,
qty INT NOT NULL,test
PRIMARY KEY (empid,ordermonth)
);

INSERT INTO EmpOrders
SELECT a.employeeid,orderdate AS Order date,SUM(quantity) AS qty
FROM orders a
INNER JOIN orderdetails b
ON a.orderid=b.orderid
GROUP BY employid,DATE_FORMAT(orderdate,'%Y-m');

<?php
$sql = "INSERT INTO emporders SELECT %s,'%s-%02d-01',%s;".'<br />';
$insert_sql = '';
for($empid=1;$empid<=8;$empid++)
{
  for($year=2009;$year<=2015;$year++)
  {
    for($month=1;$month<=12;$month++)
    {
      $num = rand(20,800);
      $insert_sql .= sprintf($sql,$empid,$year,$month,$num);
    }
    $insert_sql .= '<br />';
  }
}
echo $insert_sql;