如何在 LATERAL VIEW EXPLODE 中使数组动态化?
How do I make array dynamic in LATERAL VIEW EXPLODE?
我在 table.
中有一堆学生记录
school stduent_id start_date end_date
111 123 2010-02-03 2012-02-03
222 345 2013-02-03 2014-02-03
222 567 2015-02-03 2018-02-03
我想统计每个学校每年有多少学生,比如说从2014年一直到2021年。
目前,我使用的是横向视图,但它是硬编码的:
SELECT school
, yrs
, COUNT(DISTINCT stduent_id) AS cnt
FROM TABLE
LATERAL VIEW EXPLODE(ARRAY(2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021))a AS yrs
WHERE 1=1
AND YEAR(start_date) <= yrs
AND YEAR(end_date) >= yrs
我希望这个在年份移动时自动更新,例如,现在应该是 2014-2021,明年应该是 2015-2022。
知道我应该怎么做吗?谢谢!
SELECT school, yrs, COUNT(DISTINCT stduent_id) AS cnt
FROM TABLE
WHERE yrs
Between Year((DATEADD(YEAR,-7,GETDATE())))
and
Year(GETDATE())
您可以使用 posexplode 生成年份范围:
with year_range as(--7 years back from current year till current year
select year(current_date)-7+i as yr
from ( select posexplode(split(space(7),' ')) as (i,x)
) s
)
SELECT school
, y.yr
, COUNT(DISTINCT stduent_id) AS cnt
FROM TABLE
CROSS JOIN year_range y
GROUP BY school, y.yr
WHERE 1=1
AND YEAR(start_date) <= y.yr
AND YEAR(end_date) >= y.yr
我在 table.
中有一堆学生记录school stduent_id start_date end_date
111 123 2010-02-03 2012-02-03
222 345 2013-02-03 2014-02-03
222 567 2015-02-03 2018-02-03
我想统计每个学校每年有多少学生,比如说从2014年一直到2021年。
目前,我使用的是横向视图,但它是硬编码的:
SELECT school
, yrs
, COUNT(DISTINCT stduent_id) AS cnt
FROM TABLE
LATERAL VIEW EXPLODE(ARRAY(2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021))a AS yrs
WHERE 1=1
AND YEAR(start_date) <= yrs
AND YEAR(end_date) >= yrs
我希望这个在年份移动时自动更新,例如,现在应该是 2014-2021,明年应该是 2015-2022。
知道我应该怎么做吗?谢谢!
SELECT school, yrs, COUNT(DISTINCT stduent_id) AS cnt
FROM TABLE
WHERE yrs
Between Year((DATEADD(YEAR,-7,GETDATE())))
and
Year(GETDATE())
您可以使用 posexplode 生成年份范围:
with year_range as(--7 years back from current year till current year
select year(current_date)-7+i as yr
from ( select posexplode(split(space(7),' ')) as (i,x)
) s
)
SELECT school
, y.yr
, COUNT(DISTINCT stduent_id) AS cnt
FROM TABLE
CROSS JOIN year_range y
GROUP BY school, y.yr
WHERE 1=1
AND YEAR(start_date) <= y.yr
AND YEAR(end_date) >= y.yr