Question

从我发现有用的StackOverflow.com的this其他帖子中获取。

我想知道是否可以使用我没有明确定义的日期范围进行分组。

所以要澄清一下，说我有一个名为Person的表和一个名为Date of Birth的列。

我想分组并计算一段时间内出生的人数。

所以它看起来像这样。

Born Count

Mar1980 25

Apr1980 452

1980年5月42

...

Dec1993 452

这段时间可能是数周，数月和季度。

如果我使用其他解决方案，我需要指定每个日期范围，即使是数月和数年，也需要很长时间，因为人们的出生日期差异很大。

select t.DOB as [dob], count(*) as [number of occurences]
from (
      select user_id,
         case when date >= '1980-01-01' and date < '1980-02-01 then 'Jan 1980'
         when date >= '1980-02-01' and date < '1980-03-01 then 'Feb 1980'
         ...
         when date >= '1990-03-01' and date < '1990-04-01 then 'Mar 1990'
        else 'Null' end as DOB
     from Person) t
group by t.DOB

您能想到的任何解决方案是否可以让我只指定我希望数据范围的间隔大小并按这些日期范围分组？

Answer 1

这样的事情会解决你所追求的问题吗？诀窍是使用和滥用CONVERT函数来让您的时间段很好地滚动，然后使用DENSE_RANK将其减少为单调增加的序列。

WITH DUMMY_DATA AS
(
-- use a convert with a type of 112 to coerce dates to
-- YYYY-MM format and truncate days
-- Be creative, use to generate whatever bands you desire
SELECT CONVERT(char(7), '2011-06-01', 112) AS period, 'stuff' AS junk
UNION ALL SELECT CONVERT(char(7), '2011-05-01', 112) AS period, 'more stuf' AS junk
UNION ALL SELECT CONVERT(char(7), '2011-05-01', 112) AS period, 'more stuf1' AS junk
UNION ALL SELECT CONVERT(char(7), '2011-05-01', 112) AS period, 'more stuf2' AS junk
UNION ALL SELECT CONVERT(char(7), '2011-05-01', 112) AS period, 'more stuf3' AS junk
UNION ALL SELECT CONVERT(char(7), '2011-05-01', 112) AS period, 'more stu4f' AS junk
UNION ALL SELECT CONVERT(char(7), '2011-05-01', 112) AS period, 'more stuf5' AS junk
UNION ALL SELECT CONVERT(char(7), '2011-05-01', 112) AS period, 'more stuf7' AS junk
UNION ALL SELECT CONVERT(char(7), '2011-05-01', 112) AS period, 'more stuf8' AS junk
UNION ALL SELECT CONVERT(char(7), '2011-05-01', 112) AS period, 'more stuf9' AS junk
UNION ALL SELECT CONVERT(char(7), '2011-05-01', 112) AS period, 'more stuf0' AS junk
)
, BANDS AS
(
-- Using our data, create bands in case you want to look
-- at groupings 
SELECT
    D.*
,   DENSE_RANK() OVER (ORDER BY D.period ASC) AS banding
FROM
    DUMMY_DATA D
)
, ROLLUPS AS
(
-- ROll up based on our banding
SELECT
    B.period
,   B.banding
,   COUNT(1) AS row_count
FROM
    BANDS B
GROUP BY
    B.period
,   B.banding

） SELECT * FROM ROLLUPS R

使用上面的内容，我得到像

这样的输出

[period]   [band]  [row_count]
2011-05    1       10
2011-06    2       1

Answer 2

你可能会使用类似的东西并利用函数DATEPART

请。不要忘记取消注释要测试的语句。

WITH DummyTable AS (
SELECT '05/01/2011' AS DateOfBirth, 'Peter' AS CustomerName UNION ALL
SELECT '06/02/2011' AS DateOfBirth, 'Bill' AS CustomerName UNION ALL
SELECT '05/01/2011' AS DateOfBirth, 'Charles' AS CustomerName UNION ALL
SELECT '07/13/2010' AS DateOfBirth, 'Maria' AS CustomerName UNION ALL
SELECT '01/01/2009' AS DateOfBirth, 'Theresa' AS CustomerName UNION ALL
SELECT '05/01/2011' AS DateOfBirth, 'Steven' AS CustomerName UNION ALL
SELECT '06/02/2011' AS DateOfBirth, 'Matthew' AS CustomerName UNION ALL
SELECT '07/13/2010' AS DateOfBirth, 'Rachel' AS CustomerName UNION ALL
SELECT '05/01/2011' AS DateOfBirth, 'Molly' AS CustomerName UNION ALL
SELECT '07/13/2010' AS DateOfBirth, 'Alex' AS CustomerName UNION ALL
SELECT '08/01/2009' AS DateOfBirth, 'John' AS CustomerName UNION ALL
SELECT '07/13/2010' AS DateOfBirth, 'Ann' AS CustomerName UNION ALL
SELECT '05/01/2011' AS DateOfBirth, 'Jay' AS CustomerName
) 
--By Month

--SELECT DATENAME(month, DateOfBirth)+DATENAME(year, dateofBirth), COUNT(*)
--FROM DummyTable
--GROUP BY DATENAME(month, DateOfBirth)+DATENAME(year, dateofBirth)


--BY Quarter

--SELECT CAST(DATEPART(QUARTER, DateOfBirth) AS Varchar)+' quarter '+DATENAME(year, dateofBirth), COUNT(*)
--FROM DummyTable
--GROUP BY CAST(DATEPART(QUARTER, DateOfBirth) AS Varchar)+' quarter '+DATENAME(year, dateofBirth)

如何按SQL中的日期范围进行分组

2 个答案: