本文实例讲述了mysql滑动订单问题原理与解决方法。分享给大家供大家参考，具体如下：

先根据以下代码来创建表MonthlyOrders并导入一定的数据

CREATE TABLE MonthlyOrders(ordermonth DATE,ordernum INT UNSIGNED,PRIMARY KEY (ordermonth));

INSERT INTO MonthlyOrders SELECT '2010-02-01',23;INSERT INTO MonthlyOrders SELECT '2010-03-01',26;INSERT INTO MonthlyOrders SELECT '2010-04-01',24;INSERT INTO MonthlyOrders SELECT '2010-05-01',27;INSERT INTO MonthlyOrders SELECT '2010-06-01',26;INSERT INTO MonthlyOrders SELECT '2010-07-01',32;INSERT INTO MonthlyOrders SELECT '2010-08-01',34;INSERT INTO MonthlyOrders SELECT '2010-09-01',30;INSERT INTO MonthlyOrders SELECT '2010-10-01',31;INSERT INTO MonthlyOrders SELECT '2010-11-01',32;INSERT INTO MonthlyOrders SELECT '2010-12-01',33;INSERT INTO MonthlyOrders SELECT '2011-01-01',31;INSERT INTO MonthlyOrders SELECT '2011-02-01',34;INSERT INTO MonthlyOrders SELECT '2011-03-01',34;INSERT INTO MonthlyOrders SELECT '2011-04-01',38;INSERT INTO MonthlyOrders SELECT '2011-05-01',39;INSERT INTO MonthlyOrders SELECT '2011-06-01',35;INSERT INTO MonthlyOrders SELECT '2011-07-01',49;INSERT INTO MonthlyOrders SELECT '2011-08-01',56;INSERT INTO MonthlyOrders SELECT '2011-09-01',55;INSERT INTO MonthlyOrders SELECT '2011-10-01',74;INSERT INTO MonthlyOrders SELECT '2011-11-01',75;INSERT INTO MonthlyOrders SELECT '2011-12-01',14;

滑动订单问题是指为每个月返回上一年度（季度或月度）的滑动订单数，即每个月份N，返回N-11到月份N的订单总数。这里，假设月份序列中不存在间断。

执行下面的SQL查询实现每个月返回上一年度的滑动订单总数

SELECTDATE_FORMAT(a.ordermonth, '%Y%m') AS frommonth,DATE_FORMAT(b.ordermonth, '%Y%m') AS tomonth,SUM(c.ordernum) AS ordersFROM monthlyorders aINNER JOIN monthlyorders bON DATE_ADD(a.ordermonth, INTERVAL 11 MONTH) = b.ordermonthINNER JOIN monthlyorders cON c.ordermonth BETWEEN a.ordermonth AND b.ordermonthGROUP BY a.ordermonth,b.ordermonth;

运行结果如下图

该查询首先对MonthlyOrders表进行自连接。a表用做下边界(frommonth)，b表用做上边界(tomonth)。连接的条件为:

DATE_ADD(a.ordermonth, INTERVAL 11 MONTH) = b.ordermonth

例如，a表中的2010年2月将匹配2011年1月。

完成自连接之后，需要对订单进行统计。这时需要再进行一次自连接，得到范围内每个月的订单数量。因此连接的条件为

c.ordermonth BETWEEN a.ordermonth AND b.ordermonth

基于上述方法，我们还可以统计每个季度订单的情况，以此作为和同比增长的比较依据。

SELECTDATE_FORMAT(a.ordermonth, '%Y%m') AS frommonth,DATE_FORMAT(b.ordermonth, '%Y%m') AS tomonth,SUM(c.ordernum) AS ordersFROM monthlyorders aINNER JOIN monthlyorders bON DATE_ADD(a.ordermonth, INTERVAL 2 MONTH) = b.ordermonthAND MONTH(a.ordermonth) % 3 = 1INNER JOIN monthlyorders cON c.ordermonth BETWEEN a.ordermonth AND b.ordermonthGROUP BY a.ordermonth,b.ordermonth;

运行结果如下图

更多关于MySQL相关内容感兴趣的读者可查看本站专题：《MySQL查询技巧大全》、《MySQL常用函数大汇总》、《MySQL日志操作技巧大全》、《MySQL事务操作技巧汇总》、《MySQL存储过程技巧大全》及《MySQL数据库锁相关技巧汇总》

希望本文所述对大家MySQL数据库计有所帮助。