Sql server 使用布尔条件计算具有条件sql的月份
我有一张这样的桌子:Sql server 使用布尔条件计算具有条件sql的月份,sql-server,sql-server-2012,gaps-and-islands,Sql Server,Sql Server 2012,Gaps And Islands,我有一张这样的桌子: ---id---datetime---month---active 1 2016-12-01 Dec-16 0 1 2016-12-02 Dec-16 1 1 2017-01-28 Jan-17 1 1 2017-02-03 Feb-17 0 1 2017-02-24 Feb-17 0 1 2017-03-05 Mar-17 0 1 2017-03-24 Mar-1
---id---datetime---month---active
1 2016-12-01 Dec-16 0
1 2016-12-02 Dec-16 1
1 2017-01-28 Jan-17 1
1 2017-02-03 Feb-17 0
1 2017-02-24 Feb-17 0
1 2017-03-05 Mar-17 0
1 2017-03-24 Mar-17 1
1 2017-04-02 Apr-17 1
1 2017-04-25 Apr-17 1
1 2017-05-02 May-17 1
1 2017-05-28 May-17 0
我希望得到这样的结果:
---id---monthCount---Active
1 1 0
1 2 1
1 2 0
1 3 1
1 1 0
该表的id不超过1个id
现在,我只是通过使用分区和排序(按id
,active
和排序(按datetime
)来获得最小日期和最大日期之间的差异,但这给了我从第一次变为1到最后变为0的月份。我希望通过每次更改active
将其详细分开
我怎样才能做到这一点 您可以使用行号的差异来识别组(这是一个间隙和孤岛问题)。最后的解决方案需要
计数(不同)
:
这是假设数据是按id、month、active排序的——这是问题中数据的排序。最好使用一个列来明确定义行的排序顺序。在sql server 2012+中,您可以像这样使用
LAG
DECLARE @SampleData AS TABLE
(
id int,
[datetime] datetime,
active bit
)
;WITH temp AS
(
SELECT sd.id,
sd.active,
sd.[datetime],
lag(sd.active) over(PARTITION BY sd.id ORDER BY sd.datetime) AS previousActive,
lag(sd.id) over( ORDER BY sd.id, sd.datetime) AS previousId
FROM @SampleData sd
)
,temp1 AS
(
SELECT *,
sum(CASE WHEN t.previousActive IS NULL OR t.previousActive != t.active OR t.id != t.previousId THEN 1
ELSE 0 END)
OVER(PARTITION BY t.id ORDER BY t.[datetime]) AS groupid
FROM temp t
)
SELECT t.id, count(DISTINCT month(t.datetime)) AS monthCount, t.active
FROM temp1 t
GROUP BY id, t.groupid, t.active
演示链接:括号是什么?当我试图运行代码时,由于语法不正确,我遇到了一个错误,而且我从未见过这样的分组。你能解释一下吗?这是个错误吗?
DECLARE @SampleData AS TABLE
(
id int,
[datetime] datetime,
active bit
)
;WITH temp AS
(
SELECT sd.id,
sd.active,
sd.[datetime],
lag(sd.active) over(PARTITION BY sd.id ORDER BY sd.datetime) AS previousActive,
lag(sd.id) over( ORDER BY sd.id, sd.datetime) AS previousId
FROM @SampleData sd
)
,temp1 AS
(
SELECT *,
sum(CASE WHEN t.previousActive IS NULL OR t.previousActive != t.active OR t.id != t.previousId THEN 1
ELSE 0 END)
OVER(PARTITION BY t.id ORDER BY t.[datetime]) AS groupid
FROM temp t
)
SELECT t.id, count(DISTINCT month(t.datetime)) AS monthCount, t.active
FROM temp1 t
GROUP BY id, t.groupid, t.active