MYSQL基于提供的月份排序

Question

我有两个给定结构的表:

表格1:

ST_Id  ST_Name  
1       xx  
2       yy

表2:

AT_Id   AT_Amt  ST_ID   Date

1       500      1     2015-11-17
2       1000     1     2015-11-15
3       300      1     2015-12-1
4       200      2     2015-11-2

我希望逐月从mysql订单中获得结果.在我的php页面中,我有一个用于显示数据的表结构,如下所示

State       December    November    September

xx          300         1500          0
yy           0          200           0

除了这几个月,我还有一个排序链接,用于根据月份对金额进行排序.因此,当我单击对应于11月份的排序图像时,它应该根据该列中的金额顺序列出表格数据.如果我点击升序排序,它应该列出,如,

State       December    November    September

yy            0          200         0
xx            300        1500        0

我尝试了以下查询:

SELECT ST.ST_Name,SUM(AT.AT_Amt)     
            FROM `Table2` AS AT 
            LEFT JOIN Table1 AS ST ON AT.ST_Id = ST.ST_Id  
             WHERE AT.Date BETWEEN '2015-04-01' AND '2015-12-31' GROUP BY MONTH( AT.Date) ORDER BY IF(MONTH(AT.Date) = 11 ,  SUM(AT.AT_Amt)  , MONTH( AT.Date)) ASC 

此查询返回如下所示的数据.

ST_Name   SUM(AT.AT_Amt)
xx        300
xx        1700

但预期的结果是:

ST_Name   SUM(AT.AT_Amt)
yy        200
xx        1500

有人可以帮我解决这个问题吗？提前致谢.

Answer 1

你可以这样做:

SELECT
    st_name,
    SUM(CASE WHEN MONTH(dt) = 12 THEN at_amt ELSE 0 END) AS December,
    SUM(CASE WHEN MONTH(dt) = 11 THEN at_amt ELSE 0 END) AS November,
    SUM(CASE WHEN MONTH(dt) = 10 THEN at_amt ELSE 0 END) AS September
FROM table2
INNER JOIN table1 ON table1.st_id = table2.st_id
GROUP BY st_name;

一旦将数据导入PHP,您就可以使用JavaScript来使用TableSorter或类似的库进行客户端排序.这样排序不会导致重新查询数据库的费用.

您的数据结果将是:

+---------+----------+----------+-----------+
| st_name | December | November | September |
+---------+----------+----------+-----------+
| xx      |      300 |     1500 |         0 |
| yy      |        0 |      200 |         0 |
+---------+----------+----------+-----------+

点击下面的链接查看正在运行的演示:

SQLFiddle

编辑:

根据您的评论,这是您需要的吗？

SELECT 
  ST.ST_Name,
  SUM(AT.AT_Amt) as Amount
FROM `Table2` AS AT 
LEFT JOIN Table1 AS ST ON AT.ST_Id = ST.ST_Id  
WHERE AT.dt BETWEEN '2015-04-01' AND '2015-12-31' 
AND MONTH(AT.dt) = 11
GROUP BY ST.ST_Name
ORDER BY Amount

示例:http://sqlfiddle.com/#!9/51c7c/7用于演示

结果:

| st_name | Amount |
|---------|--------|
|      yy |    200 |
|      xx |   1500 |