如果 Value 连续两个月出现，则在 sql 中只显示一个月

Question

我想连续几个月检查 ID，如果连续两个月存在相同的 ID，则仅考虑第 1 个月的 ID。 如果 ID 不是连续月份，则显示按开始日期月份分组的不同 ID。（我们只考虑开始日期） 例如，ID 1 存在于 1 月和 2 月的开始日期月份，那么此 ID 的不同计数将在 1 月为 1，但 ID 2 和 3 是什么
出现在 1 月和 3 月以及 2 月和 5 月 Resp，现在我想在 1 月和 3 月看到这个不同的 ID 计数。 当前数据

表1：

ID    StartDate      EndDate
1     2017-01-12     2017-01-28
1     2017-01-19     2017-01-28
1     2017-01-29     2017-02-11
1     2017-02-01     2017-02-11
1     2017-02-19     2017-02-24
2     2017-01-12     2017-01-28
2     2017-01-19     2017-01-28
2     2017-03-09     2017-03-20
3     2017-02-12     2017-02-28
3     2017-02-19     2017-02-28
3     2017-05-05     2017-05-29
3     2017-05-09     2017-05-29

我尝试了以下逻辑 bt 我知道我在这里遗漏了一些东西。

select t.* from Table1 t
join Table1 t t1
on t1.ID=t.ID 
and datepart(mm,t.StartDate)<> datepart(mm,t1.StartDate)+1

预期结果：

DistinctCount     StartDateMonth(In Numbers)
   1                 1(Jan)
   2                 1(Jan)
   2                 3(March)
   3                 2(Feb)
   3                 5(May)

感谢任何帮助！

Answer 1

这是我的解决方案。对此的想法是：

1) 将所有日期四舍五入到当月的第一天，然后使用 (ID, StartDateRounded) 的不同数据集。从您的数据集中，结果应如下所示：

ID     StartDateRounded

1      2017-01-01
1      2017-02-01
2      2017-01-01
2      2017-03-01
3      2017-02-01
3      2017-05-01

2) 从这个合并的数据集中，按 ID 查找上个月没有记录的所有记录（这意味着它不是连续的月份，因此是新数据点的开始）。这是你的最终数据集

with DatesTable AS 
(
  SELECT DISTINCT ID
    ,DATEADD(month,DateDiff(month,0,StartDate),0) StartDateRounded
    ,DATEADD(month,DateDiff(month,0,StartDate)+1,0) StartDateRoundedPlusOne
  FROM Table1
)
SELECT t1.ID, DatePart(month,t1.StartDateRounded) AS StartDateMonth
  FROM DatesTable t1
    LEFT JOIN DatesTable t2
      ON t1.ID = t2.ID
        AND t1.StartDateRounded = t2.StartDateRoundedPlusOne
WHERE t2.ID IS NULL; --Verify no record exists for prior month

sqlfiddler 供参考。让我知道这是否有帮助

Answer 2

只需要利用内部查询上的lag来比较行之间的值，并将有问题的逻辑应用于中间查询，然后进行最终选择。

/*SAMPLE DATA*/
create table #table1
    (
        ID int not null
        , StartDate date not null
        , EndDate date null
    )

insert into #table1
values (1, '2017-01-12', '2017-01-28')
    , (1, '2017-01-19', '2017-01-28')
    , (1, '2017-01-29', '2017-02-11')
    , (1, '2017-02-01', '2017-02-11')
    , (1, '2017-02-19', '2017-02-24')
    , (2, '2017-01-12', '2017-01-28')
    , (2, '2017-01-19', '2017-01-28')
    , (2, '2017-03-09', '2017-03-20')
    , (3, '2017-02-12', '2017-02-28')
    , (3, '2017-02-19', '2017-02-28')
    , (3, '2017-05-05', '2017-05-29')
    , (3, '2017-05-09', '2017-05-29')

/*ANSWER*/

--Final Select
select c.ID
, c.StartDateMonth
from (
    --Compare record values to rule a record in/out based on OP's logic
    select b.ID
    , b.StartDateMonth
    , case when b.StartDateMonth = b.StartDateMonthPrev then 0 --still the same month?
           when b.StartDateMonth = b.StartDateMonthPrev + 1 then 0 --immediately prior month?
           when b.StartDateMonth = 1 and b.StartDateMonthPrev = 12 then 0 --Dec/Jan combo
           else 1
      end as IncludeFlag
    from (
        --pull StartDateMonth of previous record into current record
        select a.ID
        , datepart(mm, a.StartDate) as StartDateMonth
        , lag(datepart(mm, a.StartDate), 1, NULL) over (partition by a.ID order by a.StartDate asc) as StartDateMonthPrev
        from #table1 as a
        ) as b
    ) as c
where 1=1
and c.IncludeFlag = 1

输出：

+----+----------------+
| ID | StartDateMonth |
+----+----------------+
|  1 |              1 |
|  2 |              1 |
|  2 |              3 |
|  3 |              2 |
|  3 |              5 |
+----+----------------+

Answer 3

试试下面的查询，

SELECT  ID,MIN(YEARMONTH) AS  YEARMONTH
FROM    (
        SELECT  ID
                ,YEAR([StartDate])*100+MONTH([StartDate])       AS YEARMONTH
                ,LAG(YEAR([StartDate])*100+MONTH([StartDate])) 
                                            OVER(ORDER BY ID)   AS PREVYEARMONTH
                ,ROW_NUMBER() OVER(ORDER BY ID)                 AS ROW_NO
        FROM    @Table1
        GROUP BY ID,((YEAR([StartDate])*100)+MONTH([StartDate]))
)   AS T
GROUP BY ID
    ,(CASE WHEN YEARMONTH - PREVYEARMONTH > 1 THEN ROW_NO ELSE 0 END)
ORDER BY ID

输出：

ID  YEARMONTH
1   201701
2   201701
2   201703
3   201702
3   201705

Answer 4

谢谢大家。大多数逻辑似乎都有效..但我只尝试了以下一个，我很擅长这个。

SELECT t1.ID, DatePart(month,t1.Startdate) AS StartDateMonth
  FROM DatesTable t1
    LEFT JOIN DatesTable t2
      ON t1.ID = t2.ID
        AND DatePart(month,t1.Startdate)  = DatePart(month,t2.Startdate)+1
WHERE t2.ID IS NULL;

再次感谢

Answer 5

好的，我没有检查就写了我的第一个查询，相信它会正常工作。这是我的更新版本，应该比其他解决方案更快

select
    id
    , min(st)%12 --this will return start month
    , min(st)/12 + 1 --this will return year, just in case if you need it
from (
    select
        id, st, gr = st - row_number() over (partition by ID order by st)
    from (
        select
            distinct ID, st = (year(StartDate) - 1) * 12 + month(StartDate)
        from
            #table2
    ) t
) t
group by id, gr