【Transact-SQL】统计某字段中的值第一次出现后的2小时内出现的次数
原文:【Transact-SQL】统计某字段中的值第一次出现后的2小时内出现的次数
table1
name createdate
a 2011-03-01 10:00:00
a 2011-03-01 11:00:00
a 2011-03-01 14:00:00
b 2011-03-01 13:00:00
b 2011-03-01 13:20:00
b 2011-03-01 14:00:00 查询结果为
name createdate count
a 2011-03-01 10:00:00 2
a 2011-03-01 14:00:00 1
b 2011-03-01 13:00:00 3 就相当于是统计name字段中的值在第一次出现后的2小时内，总共出现了几次？
这个是网上的解答：
-
declare @table1 table(name nvarchar,createdate smalldatetime)
-
-
insert into @table1
-
select 'a','2011-03-01 10:00:00'
-
union all select 'a','2011-03-01 11:00:00'
-
union all select 'a','2011-03-01 14:00:00'
-
union all select 'b','2011-03-01 13:00:00'
-
union all select 'b','2011-03-01 13:20:00'
-
union all select 'b','2011-03-01 14:00:00'
-
-
select name,
-
createdate,
-
(select count(createdate)
-
from @table1 b
-
where a.name=b.name and
-
a.createdate<=b.createdate and
-
dateadd(hh,2,a.createdate) >= b.createdate
-
) as count
-
-
from @table1 a
-
where not exists
-
(select 1 from
-
@table1 b
-
where a.name=b.name and
-
a.createdate>b.createdate and
-
a.createdate<dateadd(hh,2,b.createdate))
-
group by name,createdate
但是这个解答其实是有问题的，当把临时表中的第3条数据的createdate改为'2011-03-01 12:00:00'，那么显示的结果是：
name createdate count
a 2011-03-01 10:00:00 3
b 2011-03-01 13:00:00 3
在其中没有包括createdate为'2011-03-01 12:00:00'的记录，因为这个时间到为'2011-03-01 10:00:00'是超过2个小时了，也就是说为'2011-03-01 10:00:00'是第一个出现时间，到为'2011-03-01 11:59:59'为止，接下来应该是从'2011-03-01 12:00:00'开始的下个区间了，而这里显然是有问题的。
以下是我写的解法，虽然效率不是太高，但是能解决这个问题：
-
declare @table1 table(name nvarchar,createdate smalldatetime)
-
-
insert into @table1
-
select 'a','2011-03-01 10:00:00'
-
union all select 'a','2011-03-01 11:00:00'
-
union all select 'a','2011-03-01 12:00:00'
-
union all select 'b','2011-03-01 13:10:00'
-
union all select 'b','2011-03-01 13:20:00'
-
union all select 'b','2011-03-01 14:30:00'
-
union all select 'b','2011-03-01 15:15:00'
-
union all select 'b','2011-03-01 16:00:00'
-
union all select 'b','2011-03-01 17:00:00'
-
-
-
-
;with aa --按照name分区，同时按照createdate排序编号
-
as
-
(
-
select name,
-
createdate,
-
ROW_NUMBER() over(partition by name
-
order by createdate) as k1
-
from @table1
-
),
-
-
r
-
as
-
(
-
select v.name,
-
starts=v.k1, --区间开始的编号
-
-
ends=isnull(
-
min(case when v.k1<a.k1
-
and DATEADD(hour,2,v.createdate) <= a.createdate
-
then a.k1
-
else null
-
end)-1,
-
-
max(case when v.k1<a.k1
-
then a.k1
-
else v.k1
-
end)
-
), --区间结尾的编号
-
-
isnull(
-
min(case when v.k1<a.k1
-
and DATEADD(hour,2,v.createdate) <= a.createdate
-
then a.k1
-
else null
-
end)-1,
-
-
max(case when v.k1<a.k1
-
then a.k1
-
else v.k1
-
end)
-
) - v.k1 as diff --区间结尾编号与区间开始编号之间的差值
-
-
from aa v
-
inner join aa a
-
on v.name = a.name --只关联name相等的
-
group by v.name,
-
v.k1
-
having isnull(
-
min(case when v.k1<a.k1
-
and DATEADD(hour,2,v.createdate) <= a.createdate
-
then a.k1
-
else null
-
end)-1,
-
-
max(case when v.k1<a.k1
-
then a.k1
-
else v.k1
-
end)
-
) >=v.k1
-
and
-
isnull(
-
max(case when v.k1>a.k1 and
-
DATEADD(hour,-2,v.createdate) >= a.createdate
-
then v.k1 - 1
-
else null
-
end) + 1,
-
-
min(case when v.k1>a.k1
-
then a.k1
-
else v.k1
-
end)
-
) = v.k1
-
)
-
-
--select * from r
-
-
-
select aa.name,
-
aa.createdate,
-
diff + 1
-
from r
-
inner join aa
-
on aa.name = r.name
-
and aa.k1 =r.starts
-
where not exists
-
(select 1
-
from r rr
-
where rr.name = r.name and
-
rr.starts <> r.starts and
-
rr.starts < r.starts and
-
(rr.ends = r.ends or
-
rr.ends = r.starts)
-
)
不过发现我的这个解法也是有问题的，最大的问题在与不能准确的确定上限在那里，还得继续考虑问题的解法。
下面这个也是有问题的：
-
declare @table1 table(name nvarchar,createdate smalldatetime)
-
-
insert into @table1
-
select 'a','2011-03-01 10:00:00'
-
union all select 'a','2011-03-01 11:00:00'
-
union all select 'a','2011-03-01 12:00:00'
-
-
--union all select 'b','2011-03-01 13:10:00'
-
--union all select 'b','2011-03-01 13:20:00'
-
--union all select 'b','2011-03-01 14:30:00'
-
--union all select 'b','2011-03-01 15:15:00'
-
--union all select 'b','2011-03-01 16:00:00'
-
--union all select 'b','2011-03-01 17:15:00'
-
-
-
-
;with a --按照name分区，同时按照createdate排序编号
-
as
-
(
-
select name,
-
createdate,
-
ROW_NUMBER() over(partition by name
-
order by createdate) as k1
-
from @table1
-
),
-
-
c
-
as
-
(
-
select a1.name,
-
a1.createdate,
-
a1.k1,
-
MIN(a2.createdate) as nextCreatedate,
-
MIN(a2.k1) as nextK1
-
from a a1
-
inner join a a2
-
on a1.name = a2.name
-
and a2.createdate < DATEADD(hour,2,a1.createdate)
-
and a2.createdate >= a1.createdate
-
and a1.k1 <= a2.k1
-
group by a1.name,
-
a1.createdate,
-
a1.k1
-
),
-
-
w
-
as
-
(
-
select name,
-
createdate,
-
k1
-
-
--null,
-
--null,
-
--null
-
from a
-
where k1 = 1
-
-
union all
-
-
select c.name,
-
c.nextCreatedate,
-
c.nextK1
-
-
from W
-
inner join a
-
on a.name = w.name
-
and dateadd(hour,2,w.createdate) <= a.createdate
-
and w.k1 <= a.k1
-
and w.createdate <> '2011-03-01 12:00:00'
-
inner join c
-
on w.name = c.name
-
and w.createdate = c.createdate
-
and w.k1 = c.k1
-
where w.k1 <=3
-
)
-
-
SELECT *
-
FROM w
下面的解法是正确的，不过用的是T-SQL，不是纯sql了：
-
declare @table1 table(name nvarchar(100),createdate smalldatetime)
-
-
declare @table2 table(name nvarchar(100),createdate smalldatetime,rnum bigint)
-
-
declare @temp table(name nvarchar(100),createdate smalldatetime,rnum bigint)
-
-
declare @i int = 1;
-
-
insert into @table1
-
select 'a','2011-03-01 10:00:00'
-
union all select 'a','2011-03-01 11:00:00'
-
union all select 'a','2011-03-01 12:00:00'
-
-
union all select 'b','2011-03-01 13:10:00'
-
union all select 'b','2011-03-01 13:20:00'
-
union all select 'b','2011-03-01 14:30:00'
-
union all select 'b','2011-03-01 15:15:00'
-
union all select 'b','2011-03-01 16:00:00'
-
union all select 'b','2011-03-01 17:16:00'
-
union all select 'b','2011-03-01 17:15:00'
-
-
-
;with a --按照name分区，同时按照createdate排序编号
-
as
-
(
-
select name,
-
createdate,
-
ROW_NUMBER() over(partition by name
-
order by createdate) as k1
-
from @table1
-
)
-
-
insert into @table2
-
select * from a
-
-
insert into @temp
-
select name,
-
createdate,
-
rnum
-
from @table2
-
where rnum = 1
-
-
--select * from @temp
-
-
-
while @i <= (select MAX(rnum) from @table2)
-
begin
-
insert into @temp
-
-
select t2.name,
-
min(t2.createdate),
-
@i +1
-
from @temp t1
-
inner join @table2 t2
-
on t1.name = t2.name
-
and t2.createdate >= dateadd(hour,2,t1.createdate)
-
where t1.rnum = @i
-
group by t2.name
-
-
set @i = @i + 1
-
end
-
-
;with r
-
as
-
(
-
select name,
-
createdate
-
from @temp
-
group by name,
-
createdate
-
)
-
-
select r.name,
-
r.createdate,
-
COUNT(1)
-
from r
-
inner join @table1 t
-
on t.name = r.name
-
and t.createdate >= r.createdate
-
and t.createdate <DATEADD(HOUR,2,r.createdate)
-
group by r.name,
-
r.createdate
其实这个问题是个递归问题，由上一个找到下一个，但是得构造一下：
-
declare @table1 table(name nvarchar,createdate smalldatetime)
-
-
insert into @table1
-
select 'a','2011-03-01 10:00:00'
-
union all select 'a','2011-03-01 11:00:00'
-
union all select 'a','2011-03-01 12:00:00'
-
union all select 'a','2011-03-01 12:20:00'
-
-
union all select 'b','2011-03-01 13:10:00'
-
union all select 'b','2011-03-01 13:20:00'
-
union all select 'b','2011-03-01 14:30:00'
-
union all select 'b','2011-03-01 15:15:00'
-
union all select 'b','2011-03-01 16:00:00'
-
union all select 'b','2011-03-01 17:20:00'
-
union all select 'b','2011-03-01 17:15:00'
-
union all select 'b','2011-03-01 19:16:00'
-
union all select 'b','2011-03-01 17:15:00'
-
-
-
;with a --按照name分区，同时按照createdate排序编号
-
as
-
(
-
select name,
-
createdate,
-
ROW_NUMBER() over(partition by name
-
order by createdate) as k1
-
from @table1
-
),
-
-
c --对于每个时间,找到大于这个时间2小时的时间中最小那个时间
-
as
-
(
-
select a1.name,
-
a1.createdate,
-
a1.k1,
-
MIN(a2.createdate) as nextCreatedate,
-
MIN(a2.k1) as nextK1
-
from a a1
-
inner join a a2
-
on a1.name = a2.name
-
and a2.createdate >= DATEADD(hour,2,a1.createdate)
-
-
group by a1.name,
-
a1.createdate,
-
a1.k1
-
-
union all
-
-
select a.name,null,null,a.createdate,1 --构造递归运行时需要的层级
-
from a
-
where k1 = 1
-
),
-
-
w --递归查询
-
as
-
(
-
select c.name,
-
c.createdate,
-
c.k1,
-
c.nextCreatedate,
-
c.nextK1,
-
1 as lev
-
from c
-
where createdate is null
-
and k1 is null
-
-
union all
-
-
select c.name,
-
c.createdate,
-
c.k1,
-
c.nextCreatedate,
-
c.nextK1,
-
lev + 1
-
from W
-
inner join c
-
on w.name = c.name
-
and w.nextCreatedate = c.createdate
-
-
)
-
-
SELECT distinct name,
-
nextCreatedate,
-
nextK1
-
FROM w
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