<分区>
我想在包含数据和日期列的表中查找所有日期范围。 如果一天中没有数据，日期范围将被拆分。
例如，如果一个表有 1-1-2015 到 3-3-2015 之间的数据
5-1-2015 和 6-2-2015 没有数据
那么我想接收日期范围
1-1-2015 until 4-1-2015
6-1-2015 until 5-2-2015
7-2-2015 until 3-3-2015
有没有办法用 mysql 查询来做到这一点？
<分区>
我想在包含数据和日期列的表中查找所有日期范围。 如果一天中没有数据，日期范围将被拆分。
例如，如果一个表有 1-1-2015 到 3-3-2015 之间的数据
5-1-2015 和 6-2-2015 没有数据
那么我想接收日期范围
1-1-2015 until 4-1-2015
6-1-2015 until 5-2-2015
7-2-2015 until 3-3-2015
有没有办法用 mysql 查询来做到这一点？
最佳答案
计划
- cross join digits together to simulate a calendar table
- left join calendar to datasource and identify when date not present
- order over above using sql variables rgn and boundary
- aggregate over rgn, and boundary to get each region
设置
create table somedates
(
id integer primary key not null,
vdate date not null
);
drop view if exists digits_v;
create view digits_v
as
select 0 as n
union all
select 1 union all select 2 union all select 3 union all
select 4 union all select 5 union all select 6 union all
select 7 union all select 8 union all select 9
;
insert into somedates
( id, vdate )
select @id := @id + 1 as id, date_add('2015-01-01', interval a2.n * 100 + a1.n * 10 + a0.n day) as vdate
from digits_v a2
cross join digits_v a1
cross join digits_v a0
cross join ( select @id := 0 ) params
where date_add('2015-01-01', interval a2.n * 100 + a1.n * 10 + a0.n day) <= date('2015-03-03')
and date_add('2015-01-01', interval a2.n * 100 + a1.n * 10 + a0.n day) not in
(
'2015-01-05',
'2015-02-06'
)
;
查询
select rgn, min(boundary) `from`, max(boundary) `to`
from
(
select active.aday, active.present,
@rgn := if(active.present,
if(@boundary := active.aday, @rgn, @rgn),
if(@boundary := null, @rgn + 1, @rgn + 1)) as rgn,
@boundary as boundary
from
(
select date_add('2015-01-01', interval a2.n * 100 + a1.n * 10 + a0.n day) as aday,
case when sd.id is not null then true
else false
end as present
from digits_v a2
cross join digits_v a1
cross join digits_v a0
left join somedates sd
on sd.vdate = date_add('2015-01-01', interval a2.n * 100 + a1.n * 10 + a0.n day)
where date_add('2015-01-01', interval a2.n * 100 + a1.n * 10 + a0.n day) <= date('2015-03-03')
and date_add('2015-01-01', interval a2.n * 100 + a1.n * 10 + a0.n day) >= date('2015-01-01')
) active
cross join ( select @rgn := 0, @boundary := date('2015-01-01') ) params
order by active.aday
) boundaries
group by rgn
having `from` is not null
;
输出
+-----+------------+------------+
| rgn | from | to |
+-----+------------+------------+
| 0 | 2015-01-01 | 2015-01-04 |
| 1 | 2015-01-06 | 2015-02-05 |
| 2 | 2015-02-07 | 2015-03-03 |
+-----+------------+------------+
引用
关于mysql - 在 mysql 表中查找日期范围，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/33498195/