快捷導(dǎo)航

mysql滑動訂單問題原理與解決方法實例分析

更新時間：2019年12月27日 10:32:20 作者：雪山飛豬

這篇文章主要介紹了mysql滑動訂單問題原理與解決方法,結(jié)合實例形式分析了mysql滑動訂單的問題的基本原理、解決方法與相關(guān)操作注意事項,需要的朋友可以參考下

本文實例講述了mysql滑動訂單問題原理與解決方法。分享給大家供大家參考，具體如下：

先根據(jù)以下代碼來創(chuàng)建表MonthlyOrders并導(dǎo)入一定的數(shù)據(jù)

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;

滑動訂單問題是指為每個月返回上一年度（季度或月度）的滑動訂單數(shù)，即每個月份N，返回N-11到月份N的訂單總數(shù)。這里，假設(shè)月份序列中不存在間斷。

執(zhí)行下面的SQL查詢實現(xiàn)每個月返回上一年度的滑動訂單總數(shù)

SELECT
  DATE_FORMAT(a.ordermonth, '%Y%m') AS frommonth,
  DATE_FORMAT(b.ordermonth, '%Y%m') AS tomonth,
  SUM(c.ordernum) AS orders
FROM monthlyorders a
INNER JOIN monthlyorders b
  ON DATE_ADD(a.ordermonth, INTERVAL 11 MONTH) = b.ordermonth
INNER JOIN monthlyorders c
  ON c.ordermonth BETWEEN a.ordermonth AND b.ordermonth
GROUP BY a.ordermonth,b.ordermonth;

運行結(jié)果如下圖

該查詢首先對MonthlyOrders表進行自連接。a表用做下邊界(frommonth)，b表用做上邊界(tomonth)。連接的條件為:

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

例如，a表中的2010年2月將匹配2011年1月。

完成自連接之后，需要對訂單進行統(tǒng)計。這時需要再進行一次自連接，得到范圍內(nèi)每個月的訂單數(shù)量。因此連接的條件為

c.ordermonth BETWEEN a.ordermonth AND b.ordermonth

基于上述方法，我們還可以統(tǒng)計每個季度訂單的情況，以此作為和同比增長的比較依據(jù)。

SELECT
  DATE_FORMAT(a.ordermonth, '%Y%m') AS frommonth,
  DATE_FORMAT(b.ordermonth, '%Y%m') AS tomonth,
  SUM(c.ordernum) AS orders
FROM monthlyorders a
INNER JOIN monthlyorders b
  ON DATE_ADD(a.ordermonth, INTERVAL 2 MONTH) = b.ordermonth
  AND MONTH(a.ordermonth) % 3 = 1
INNER JOIN monthlyorders c
  ON c.ordermonth BETWEEN a.ordermonth AND b.ordermonth
GROUP BY a.ordermonth,b.ordermonth;

運行結(jié)果如下圖