Question

我正在尝试计算PostgreSQL中某个日期范围之间的工作日。

SELECT 
     SUM(CASE WHEN extract (dow FROM foo) IN(1,2,3,4,5) THEN 1 ELSE 0 
END) 
FROM (SELECT ('2007-04-01'::date + 
(generate_series(0,'2007-04-30'::date 
 - '2007-04-01'::date)||'days')::interval) AS foo) foo

我想用名为start_date的表格中的end_date和myTable替换日期 start_date和end_date格式为yyyy-mm-dd

实际上我需要它来显示每行的营业日期差异

|start_date |end_date |
------------------------
|2018-04-01 |2018-04-30| 
|2018-05-01 |2018-05-30|

这是我的代码：

  SELECT pto.start_date, pto.end_date, 
  SUM(CASE WHEN extract (dow FROM foo) IN(1,2,3,4,5) THEN 1 ELSE 0 END) as theDIFF 
  FROM (
  SELECT start_date, (start_date::date + 
  (generate_series(0,end_date::date 
    - start_date::date)||'days')::interval) AS foo
  FROM pto
  ) foo inner join pto pto
  on pto.start_date = foo.start_date 
  group by pto.start_date, pto.end_date

我的输出：

  |start_date(date)| end_date(date) |theDiff(integer)
  ---------------------------------------------------
  |2017-06-01      |  2017-06-01    |        29     |
  |2017-05-29      |  2017-06-02    |        12     |
  ---------------------------------------------------

预期产出：

  |start_date(date)| end_date(date) |theDiff(integer)
  ---------------------------------------------------
  |2017-06-01      |  2017-06-01    |        1      |
  |2017-05-29      |  2017-06-02    |        5      |
  ---------------------------------------------------

Answer 1

您的示例代码有点令人困惑，所以只考虑工作日和您的表格，这将给出预期的输出：

CREATE TABLE myTable (start_date date, end_date date);

INSERT INTO myTable VALUES('2017-06-01', '2017-06-01'),('2017-05-29', '2017-06-02');

SELECT start_date, end_date,
       SUM(CASE WHEN EXTRACT(dow FROM days) BETWEEN 1 AND 5 THEN 1 ELSE 0 END)
  FROM myTable
 CROSS JOIN LATERAL generate_series(start_date, end_date, interval '1 day') AS days
 GROUP BY start_date, end_date;

它将生成行，每行包含start_date，end_date和一天之间的行。然后它将通过start_date，end_date和SUM（）日期进行聚合，这些日期的星期几为1到5（星期一至星期五）。

没有聚合，它看起来像这样：

 start_date |  end_date  |          days          | dow
------------+------------+------------------------+-----
 2017-06-01 | 2017-06-01 | 2017-06-01 00:00:00+02 |   4
 2017-05-29 | 2017-06-02 | 2017-05-29 00:00:00+02 |   1
 2017-05-29 | 2017-06-02 | 2017-05-30 00:00:00+02 |   2
 2017-05-29 | 2017-06-02 | 2017-05-31 00:00:00+02 |   3
 2017-05-29 | 2017-06-02 | 2017-06-01 00:00:00+02 |   4
 2017-05-29 | 2017-06-02 | 2017-06-02 00:00:00+02 |   5

并分组：

 start_date |  end_date  | sum
------------+------------+-----
 2017-06-01 | 2017-06-01 |   1
 2017-05-29 | 2017-06-02 |   5

开始日期＆amp;来自generate_series（）

1 个答案: