Question

我正在为我的网站创建一份报告，我将列出不同的房产价格 locations.I有一个如下表

 CREATE TABLE report(report_id INT NOT NULL PRIMARY KEY AUTO_INCREMENT NOT NULL,
                     Locations VARCHAR(255),
                     date VARCHAR(255),
                     ratepersqft INT);

我在表格中的值如下

 INSERT INTO report(Locations, date, ratepersqft)
             VALUES('Location A', '2012-01-16', 2500),
                   ('Location B', '2012-01-21', 1750),
                   ('Location C', '2012-01-20', 1650),
                   ('Location C', '2012-02-19', 2100),
                   ('Location A', '2012-02-18', 2560),
                   ('Location B', '2012-02-12', 1790),
                   ('Location C', '2012-03-04', 2250),
                   ('Location A', '2012-03-25', 2680),
                   ('Location B', '2012-03-05', 2540),
                   ('Location A', '2012-08-21', 2870),
                   ('Location C', '2012-09-12', 2150),
                   ('Location B', '2012-10-18', 2760);

位置|月| RatePerSqFt

 Location A     Jan              2500
 Location A     Feb              2560
 Location A     March            2680
 Location A     August           2870
 Location A     sept             2870
 Location A     oct              2870

 Location B     Jan              1750      
 Location B     Feb              1790  
 Location B     March            2540
 Location B     August           2540
 Location B     sept             2540
 Location B     oct              2760    

 Location C     Jan              1650      
 Location C     Feb              2100  
 Location C     March            2250
 Location C     August           2250
 Location C     sept             2250
 Location C     oct              2760

我想为表中可用的所有可能数据绘制值。如果您看到表格位置A没有10月份的任何条目。但由于位置B有10月份的条目，我想在输出表格中输入一个条目，其中包含位置A的最后一个月8月的登记率。

所以它显示为2870。

同样地，位置B没有8月的条目。但是由于位置A具有8月份的费率，我将带来位置B并填充上个月的2540年费率。

C相同。

如何为上述

编写查询或proc

Answer 1

看起来像分组是你正在寻找的

SELECT Locations, date_format(date,'%b') as month, sum(ratepersqft) as rates 
FROM report GROUP BY Locations, month(date);

我不确定sum。可能应该是avg或其他。

Answer 2

这是SQLFiddle demo

select Locations,year,month,
(select ratepersqft from report where 
        Locations=tl.locations
        and
        DATE_FORMAT(date,'%Y%m')<=tp.monthNum
        order by DATE_FORMAT(date,'%Y%m') desc
        limit 1) as t
       from
(select distinct Locations from report) tl,
(select distinct YEAR(date) year,
                 MONTHName(date) month,
                 DATE_FORMAT(date,'%Y%m') monthNum
                 from report) tp

order by Locations,monthNum

来自mysql表的报告数据

2 个答案:

这是SQLFiddle demo