本文例項講述了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：

先根據以下程式碼來建立表MonthlyOrders並匯入一定的資料

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，即每個月份N，返回N-11到月份N的訂單總數。這裡，假設月份序列中不存在間斷。

執行下面的SQL查詢實現每個月返回上一年度的滑動訂單總數

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;

執行結果如下圖

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

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。

完成自連線之後，需要對訂單進行統計。這時需要再進行一次自連線，得到範圍內每個月的訂單數量。因此連線的條件為

c.ordermonth BETWEEN a.ordermonth AND b.ordermonth

基於上述方法，我們還可以統計每個季度訂單的情況，以此作為和同比增長的比較依據。

SELECT
  DATE_FORMAT(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;

執行結果如下圖

更多關於MySQL相關內容感興趣的讀者可檢視本站專題：《MySQL查詢技巧大全》、《MySQL常用函式大彙總》、《MySQL日誌操作技巧大全》、《MySQL事務操作技巧彙總》、《MySQL儲存過程技巧大全》及《MySQL資料庫鎖相關技巧彙總》

希望本文所述對大家MySQL資料庫計有所幫助。