Question

我有一个表收入

+------------+--------+--------+
|    Date    | Amount | Status |
+------------+--------+--------+
| 2012-01-03 |    200 |      4 |
| 2012-02-12 |    300 |      4 |
| 2012-07-07 |    200 |      4 |
| 2012-08-15 |    300 |      4 |
| 2012-08-17 |    250 |      4 |
| 2012-09-17 |    250 |      3 |
+------------+--------+--------+

和其他一个结果

+------------+--------+
|    Date    | Amount |
+------------+--------+
| 2012-03-22 |    50  |
| 2012-07-02 |    50  |
| 2012-08-19 |    100 |
| 2012-08-22 |    70  |
+------------+--------+

当我加入这两个表（第一个只有状态为4的表）时，我需要得到这样的结果：

+------+-----------+--------+---------+--------+
| Year |   Month   | Income | Outcome | Profit |
+------+-----------+--------+---------+--------+
| 2012 | January   |    200 |       0 |    200 |
| 2012 | February  |    300 |       0 |    300 |
| 2012 | March     |      0 |      50 |    -50 |
| 2012 | April     |      0 |       0 |      0 |
| 2012 | Jun       |      0 |       0 |      0 |
| 2012 | July      |    200 |      50 |    150 |
| 2012 | August    |    550 |     170 |    380 |
| 2012 | September |      0 |       0 |      0 |
| 2012 | October   |      0 |       0 |      0 |
| 2012 | November  |      0 |       0 |      0 |
| 2012 | December  |      0 |       0 |      0 |
+------+-----------+--------+---------+--------+

如何进行查询以获得此结果？

非常感谢，

Answer 1

首先，您需要将两个表合并为一个，以便能够按月将它们组合在一起。我使用了UNION。整个查询最终都是这样的：

SELECT DATE_FORMAT(date, '%Y') AS year, DATE_FORMAT(date, '%M') AS month, SUM(income) AS income, SUM(outcome) AS outcome, (SUM(income)-SUM(outcome)) AS profit
FROM (
        SELECT date, amount AS income, 0 AS outcome FROM income_t
    UNION
        SELECT date, 0 AS income, amount AS outcome FROM outcome_t
    UNION
        SELECT '2012-01-01' AS date, 0 AS income, 0 AS outcome
    UNION
        SELECT '2012-02-01' AS date, 0 AS income, 0 AS outcome
    UNION
        SELECT '2012-03-01' AS date, 0 AS income, 0 AS outcome
    UNION
        SELECT '2012-04-01' AS date, 0 AS income, 0 AS outcome
    UNION
        SELECT '2012-05-01' AS date, 0 AS income, 0 AS outcome
    UNION
        SELECT '2012-06-01' AS date, 0 AS income, 0 AS outcome
    UNION
        SELECT '2012-07-01' AS date, 0 AS income, 0 AS outcome
    UNION
        SELECT '2012-08-01' AS date, 0 AS income, 0 AS outcome
    UNION
        SELECT '2012-09-01' AS date, 0 AS income, 0 AS outcome
    UNION
        SELECT '2012-10-01' AS date, 0 AS income, 0 AS outcome
    UNION
        SELECT '2012-11-01' AS date, 0 AS income, 0 AS outcome
    UNION
        SELECT '2012-12-01' AS date, 0 AS income, 0 AS outcome
) AS merged
GROUP BY DATE_FORMAT(date, '%Y%m')
ORDER BY date ASC;

我测试了它并且工作正常。

好吧，我确实误解了你关于所有月份的问题，但现在它就像你想要的那样。

Answer 2

首先，您需要从一个包含所有12个月的驱动程序表开始。您要求输出中不在输入中的行：

select driver.year, driver.monname, coalesce(i.amt, 0) as Income,
       coalesce(o.amt, 0) as Outcome,
       coalesce(i.amt, 0) - coalesce(o.amt, 0) as Profit
from (select 'January' as monname, 1 as mon, 2012 as yr union all
      select 'February', 2, 2012 union all
      . . .
      select 'December', 12, 2012
     ) driver left outer join
     (select year(date) as yr, month(date) as mon, sum(amount) as amt
      from income
      where status = 4
      group by year(date), month(date)
     ) i
     on driver.yr = i.yr and driver.mon = i.mon left outer join
     (select year(date) as yr, month(date) as mon, sum(amount) as amt
      from outcome
      group by year(date), month(date)
     ) o
     on driver.yr = o.yr and driver.mon = o.mon;

对于初学者来说，你的问题在几个方面相当棘手。首先，您需要驱动程序表来获取所有行（并且您需要填写表中缺少的行）。其次，您需要注意如何混合来自不同表的数据。连接选择不当会导致笛卡尔积。

Mysql：特定年份的12个月的总和，同一个月的左连接

2 个答案: