Question

我有2张桌子

tbl_vacancies_details
tbl_filled_vacancies

我想要显示一个图表，其中包含每年空缺和填充计数的总数。如何为此编写SQL查询。

 tbl_vacancies_details

    Id | Year      | Count |
    ------------------------
    1  | Jan-2014  |  10   |
    2  | Jun-2014  |  5    |
    3  | Dec-2015  |  9    |

    tbl_filled_details

    Id | Join_Date | UserId |
    ------------------------
    1  | Mar-2014  |  1     |
    2  | Dec-2014  |  6     |
    2  | Dec-2014  |  15    |
    3  | May-2016  |  3     |

我想要的输出是

Year | Total | Filled |
-----------------------
2014 | 15    | 3      |
2015 | 3     | 0      |
2016 | 0     | 3      |

Answer 1

这应该让你开始：

{{1}}

查看实际操作：SQL Fiddle

如果需要调整/进一步详细说明，请发表评论。

Answer 2

SELECT
    (CASE         
        WHEN vac.year not null then to_char(vac.Year,'YYYY')         
        ELSE to_char(det.Year,'YYYY')) as Year,
        sum(vac.Count) as Total,
        det.Count as Filled       
    FROM
        tbl_vacancies_details  vac  FULL      
    OUTER JOIN (
            SELECT
                to_char(fil.Join_Date,'YYYY') as Year,
                count(*) as Count             
            FROM
                tbl_filled_details as fil             
            GROUP BY
                to_char(fil.Join_Date,'YYYY')           
        ) det ON det.Year = vac.Year       
    GROUP BY
        to_char(vac.Year,'YYYY')

我认为这展示了如何做到这一点的想法，但我不确定它是否是runnalbe查询。您必须根据格式找到转换日期的功能。

完全超越tbl_vacancies_details每年加入内部选择（计算每年tbl_filled_details中vac的出现次数），然后显示每年的两个结果

编辑：我认为tbl_filled_details有假期的个案记录，tbl_vacancies_details已经有假期总和

Answer 3

我建议使用聚合union all查询：

select yyyy,
       sum(total) as total,
       sum(filled) as filled
from ((select year(year) as yyyy, count as total, 0 as filled
       from tbl_vacancies_details
      ) union all
      (select year(join_date) as yyyy, 0 as total, 1 as filled
       from tbl_filled_details
      )
     ) x
group by yyyy;

Here是一个SQL小提琴。

注意：我建议您不要将列命名为count和year，因为它们在SQL中用于其他目的。

如何组合具有不同数据的两个表

3 个答案: