Question

我试图在一个SQL查询中对多个表中的一些列进行求和，但我似乎得到了错误的结果。我认为我在下面提供的代码存在问题。请提供任何帮助。

item Names
 | id | name |
 | 1  |  AB  |
 | 2  |  CA  |

table1
| id  | interest | year |
| 1   |   20.00  | 2014 |
| 2   |   30.00  | 2013 |
| 1   |   10.00  | 2013 |

table2
| id  | deposit  | year |
| 1   |   10.00  | 2014 |
| 2   |   10.00  | 2014 |

这是我尝试的查询：

    SELECT 
        a.name,
        b.year,
        sum(b.interest) as 'total'
    FROM
        `table1` b
    INNER JOIN
        `item names` a
    ON
        b.id=a.id
    GROUP BY
        b.id

UNION ALL

    SELECT 
        c.name,
        d.year,
        sum(d.deposit) as 'total'
    FROM
        `table2` d
    INNER JOIN
        `item names` c
    ON
        d.id=c.id
    GROUP BY
        d.id

预期成果

更新

我试图查找特定年份和特定项目的利息和存款总额

|name   | year  |   total    |
| AB    | 2014  |    30.00   |
| AB    | 2013  |    10.00   |
| CA    | 2013  |    30.00   |
| CA    | 2014  |    10.00   |

Answer 1

也许......假设table1和table2具有相同的结构。

首先，我生成一个具有1和2的union值的集合，然后我们使用简单的聚合和group by来按名称和年份对值进行求和。

SELECT I.Name, B.year, Sum(B.Total) 
FROM item I
INNER JOIN  
(SELECT * FROM table1 UNION select * FROM table2) B
  on B.ID = I.ID
GROUP BY I.Name, B.Year

Answer 2

在您发布的查询中，您还需要按年份分组才能获得结果。然后，您可以使用UNION获取第一组中的所有行以及第二组中的所有行：

SELECT a.name, b.year, SUM(b.interest) AS total
FROM names a
JOIN table1 b ON b.id = a.id
GROUP BY a.name, b.year
UNION
SELECT a.name, c.year, SUM(c.deposit) AS total
FROM names a
JOIN table2 c ON c.id = a.id
GROUP BY a.name, c.year;

但是，这并没有给出最终结果，因为每个表格中出现的名称（例如“AB”）将出现两次。存款年度一排，年度利息一排。要组合这些，只需使用上面的子查询，总和总和再按名称和日期分组：

SELECT name, year, SUM(total) AS total
FROM(
  SELECT a.name, b.year, SUM(b.interest) AS total
  FROM names a
  JOIN table1 b ON b.id = a.id
  GROUP BY a.name, b.year
  UNION
  SELECT a.name, c.year, SUM(c.deposit) AS total
  FROM names a
  JOIN table2 c ON c.id = a.id
  GROUP BY a.name, c.year) temp
GROUP BY name, year;

以下是SQL Fiddle示例。

从MySQL中的多个表中汇总列

2 个答案: