SQL:第一次和最后一次出现之间的行数 - 有一个扭曲

SQL: Count of rows between first and last occurrence - with a twist

我想计算值第一次出现和最后一次出现之间的行数。但是,当它们之间有五个或更多个不同值的记录时,停止计数。

所以如果最后一次出现是今天,第一次出现是昨天,结果将是 2(今天加上昨天)。

如果最后一次出现是在今天,第一次出现是在 8 天前,并且两者之间没有出现,则结果将为“1”。但是,如果 3 天前发生另一次事件,结果将是 4(3+2+1 天前加上今天)。

我希望这是有道理的。

这是我的数据

Date        City    Weather
==============================
2018-08-11  Ankara  Sun
2018-08-10  Ankara  Sun
2018-08-09  Ankara  Sun
2018-08-08  Ankara  Sun
2018-08-07  Ankara  Sun
2018-08-06  Ankara  Sun
2018-08-05  Ankara  Rain
2018-08-04  Ankara  Clouds
2018-08-03  Ankara  Rain
2018-08-02  Ankara  Sun
2018-08-01  Ankara  Sun
2018-08-11  Cairo   Clouds
2018-08-10  Cairo   Sun
2018-08-09  Cairo   Sun
2018-08-08  Cairo   Sun
2018-08-07  Cairo   Sun
2018-08-06  Cairo   Sun
2018-08-05  Cairo   Clouds
2018-08-04  Cairo   Sun
2018-08-03  Cairo   Sun
2018-08-02  Cairo   Sun
2018-08-01  Cairo   Sun

我要查询的是 return 给定城市的查询,并记录当天的天气和自该天气首次出现以来的天数。但是,如果有五天或更长时间的间隔,则从 1 重新开始计数。

就像在 11th Aug 上查询 Ankara 它会 return 11 因为自 Sun 第一次出现以来已经 11 天(包括今天) .

但是对于 11th Aug 上的 Cairo 它会 return 1 而不是 7 因为它在 Clouds 之间已经超过 5 天了8 月 5 日和今天 Clouds

我已经用 first_value()、LEAD、LAG 和 ROW_NUMBER 尝试了很多东西,但没有任何意义,因为它们都惨败。

反正就在这里...

select 
 city, val,datediff(day, min(datadate), '2018-10-30') + 1 as DaysPresent
from d
where val = last_val
group by city,val;

或...

select 
        date, city, weather, datediff(day,ca.prior,d.date)+1 as daysPresent
from d
cross apply (
    select min(prev.date) as prior
    from d as prev 
    where prev.city = d.city
    and prev.date between dateadd(day,-4,d.date) and dateadd(day,0,d.date)
    and prev.weather = d.weather
    ) ca

order by city,date

预期结果

+----+---------------------+--------+---------+----------------+-------------+----------+----------------------------
|    |        date         |  city  | weather | prior_the_same | prior_types |expected  | why?
+----+---------------------+--------+---------+----------------+-------------+----------+----------------------------
|  1 | 11.08.2018 00:00:00 | Ankara | Sun     |              5 |           2 |       11 | 11t day since 1st time Sun
|  2 | 10.08.2018 00:00:00 | Ankara | Sun     |              4 |           3 |       10 | 10t day since 1st time Sun
|  3 | 09.08.2018 00:00:00 | Ankara | Sun     |              7 |           3 |        9 | 9th day since 1st time Sun
|  4 | 08.08.2018 00:00:00 | Ankara | Sun     |              7 |           3 |        8 | 8th day since 1st time Sun
|  5 | 07.08.2018 00:00:00 | Ankara | Sun     |              6 |           3 |        7 | 7th day since 1st time Sun
|  6 | 06.08.2018 00:00:00 | Ankara | Sun     |              5 |           3 |        6 | 6th day since 1st time Sun ( <5 days gap since last Sun keeps counting )
|  7 | 05.08.2018 00:00:00 | Ankara | Rain    |              2 |           3 |        3 | 3rd day since 1st time Rain
|  8 | 04.08.2018 00:00:00 | Ankara | Clouds  |              0 |           3 |        1 | 1st day Clouds
|  9 | 03.08.2018 00:00:00 | Ankara | Rain    |              0 |           2 |        1 | 1st day Rain 
| 10 | 02.08.2018 00:00:00 | Ankara | Sun     |              1 |           0 |        2 | 2nd day since 1st time Sun
| 11 | 01.08.2018 00:00:00 | Ankara | Sun     |              0 |           0 |        1 | 1st day Sun
| 12 | 11.08.2018 00:00:00 | Cairo  | Clouds  |              6 |           6 |        1 | 1st time Clouds ( >5 days gap since last Clouds resets the count )
| 13 | 10.08.2018 00:00:00 | Cairo  | Sun     |              7 |           1 |       10 | 10t day since 1st time Sun
| 14 | 09.08.2018 00:00:00 | Cairo  | Sun     |              7 |           1 |        9 | 9th day since 1st time Sun
| 15 | 08.08.2018 00:00:00 | Cairo  | Sun     |              7 |           1 |        8 | 8th day since 1st time Sun
| 16 | 07.08.2018 00:00:00 | Cairo  | Sun     |              6 |           1 |        7 | 7th day since 1st time Sun
| 17 | 06.08.2018 00:00:00 | Cairo  | Sun     |              5 |           1 |        6 | 6th day since 1st time Sun ( <5 days gap since last Sun keeps counting )
| 18 | 05.08.2018 00:00:00 | Cairo  | Clouds  |              0 |           4 |        1 | 1st time Clouds
| 19 | 04.08.2018 00:00:00 | Cairo  | Sun     |              3 |           0 |        4 | 4th day since 1st time Sun
| 20 | 03.08.2018 00:00:00 | Cairo  | Sun     |              2 |           0 |        3 | 3rd day since 1st time Sun
| 21 | 02.08.2018 00:00:00 | Cairo  | Sun     |              1 |           0 |        2 | 2nd day since 1st time Sun
| 22 | 01.08.2018 00:00:00 | Cairo  | Sun     |              0 |           0 |        1 | 1st day Sun
+----+---------------------+--------+---------+----------------+-------------+----------+----------------------------

最新

declare @day_range integer = 5;

select 
        t.date, t.city, t.weather
      , datediff(day,ca1.prior_dt,t.date)+1 as prior_the_same
      , twist.prior_types
      , twist.prior_mx_dt
from mytable t
cross apply (
    select count(prev.weather) as prior_types, max(prev.date) as prior_mx_dt
    from mytable as prev 
    where prev.city = t.city
    and prev.date between dateadd(day,-@day_range,t.date) and t.date
    and prev.weather <> t.weather
    ) twist
cross apply (
    select min(prev.date) as prior_dt
    from mytable as prev 
    where prev.city = t.city
    and (twist.prior_types < @day_range or prev.date >= twist.prior_mx_dt)
    and prev.weather = t.weather
    ) ca1

order by t.city, t.date DESC

结果:

+----+---------------------+--------+---------+----------------+-------------+---------------------+
|    |        date         |  city  | weather | prior_the_same | prior_types |     prior_mx_dt     |
+----+---------------------+--------+---------+----------------+-------------+---------------------+
|  1 | 11.08.2018 00:00:00 | Ankara | Sun     |             11 |           0 | NULL                |
|  2 | 10.08.2018 00:00:00 | Ankara | Sun     |             10 |           1 | 05.08.2018 00:00:00 |
|  3 | 09.08.2018 00:00:00 | Ankara | Sun     |              9 |           2 | 05.08.2018 00:00:00 |
|  4 | 08.08.2018 00:00:00 | Ankara | Sun     |              8 |           3 | 05.08.2018 00:00:00 |
|  5 | 07.08.2018 00:00:00 | Ankara | Sun     |              7 |           3 | 05.08.2018 00:00:00 |
|  6 | 06.08.2018 00:00:00 | Ankara | Sun     |              6 |           3 | 05.08.2018 00:00:00 |
|  7 | 05.08.2018 00:00:00 | Ankara | Rain    |              3 |           3 | 04.08.2018 00:00:00 |
|  8 | 04.08.2018 00:00:00 | Ankara | Clouds  |              1 |           3 | 03.08.2018 00:00:00 |
|  9 | 03.08.2018 00:00:00 | Ankara | Rain    |              1 |           2 | 02.08.2018 00:00:00 |
| 10 | 02.08.2018 00:00:00 | Ankara | Sun     |              2 |           0 | NULL                |
| 11 | 01.08.2018 00:00:00 | Ankara | Sun     |              1 |           0 | NULL                |
| 12 | 11.08.2018 00:00:00 | Cairo  | Clouds  |              1 |           5 | 10.08.2018 00:00:00 |
| 13 | 10.08.2018 00:00:00 | Cairo  | Sun     |             10 |           1 | 05.08.2018 00:00:00 |
| 14 | 09.08.2018 00:00:00 | Cairo  | Sun     |              9 |           1 | 05.08.2018 00:00:00 |
| 15 | 08.08.2018 00:00:00 | Cairo  | Sun     |              8 |           1 | 05.08.2018 00:00:00 |
| 16 | 07.08.2018 00:00:00 | Cairo  | Sun     |              7 |           1 | 05.08.2018 00:00:00 |
| 17 | 06.08.2018 00:00:00 | Cairo  | Sun     |              6 |           1 | 05.08.2018 00:00:00 |
| 18 | 05.08.2018 00:00:00 | Cairo  | Clouds  |              1 |           4 | 04.08.2018 00:00:00 |
| 19 | 04.08.2018 00:00:00 | Cairo  | Sun     |              4 |           0 | NULL                |
| 20 | 03.08.2018 00:00:00 | Cairo  | Sun     |              3 |           0 | NULL                |
| 21 | 02.08.2018 00:00:00 | Cairo  | Sun     |              2 |           0 | NULL                |
| 22 | 01.08.2018 00:00:00 | Cairo  | Sun     |              1 |           0 | NULL                |

在线查看:https://rextester.com/ZSHT63407


原创

样本数据为:

CREATE TABLE mytable(
   Date    DATE  NOT NULL
  ,City    VARCHAR(6) NOT NULL
  ,Weather VARCHAR(6) NOT NULL
);
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-11','Ankara','Sun');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-10','Ankara','Sun');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-09','Ankara','Sun');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-08','Ankara','Sun');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-07','Ankara','Sun');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-06','Ankara','Sun');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-05','Ankara','Rain');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-04','Ankara','Clouds');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-03','Ankara','Rain');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-02','Ankara','Sun');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-01','Ankara','Sun');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-11','Cairo','Clouds');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-10','Cairo','Sun');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-09','Cairo','Sun');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-08','Cairo','Sun');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-07','Cairo','Sun');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-06','Cairo','Sun');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-05','Cairo','Clouds');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-04','Cairo','Sun');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-03','Cairo','Sun');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-02','Cairo','Sun');
INSERT INTO mytable(Date,City,Weather) VALUES ('2018-08-01','Cairo','Sun');

使用这个查询:

declare @day_range integer = 7;
declare @ignore_range integer = 5;

select 
        t.date, t.city, t.weather
      , datediff(day,ca1.prior_dt,t.date) as prior_the_same
      , ca2.prior_types
from mytable t
cross apply (
    select min(prev.date) as prior_dt
    from mytable as prev 
    where prev.city = t.city
    and prev.date between dateadd(day,-@day_range,t.date) and t.date
    and prev.weather = t.weather
    ) ca1
cross apply (
    select count(prev.weather) as prior_types
    from mytable as prev 
    where prev.city = t.city
    and prev.date between dateadd(day,-@day_range,t.date) and t.date
    and prev.weather <> t.weather
    ) ca2
order by t.city, t.date DESC

结果如下:

+----+---------------------+--------+---------+----------------+-------------+----------+
|    |        date         |  city  | weather | prior_the_same | prior_types |expected? |
+----+---------------------+--------+---------+----------------+-------------+----------+
|  1 | 11.08.2018 00:00:00 | Ankara | Sun     |              5 |           2 |          |
|  2 | 10.08.2018 00:00:00 | Ankara | Sun     |              4 |           3 |          |
|  3 | 09.08.2018 00:00:00 | Ankara | Sun     |              7 |           3 |          |
|  4 | 08.08.2018 00:00:00 | Ankara | Sun     |              7 |           3 |          |
|  5 | 07.08.2018 00:00:00 | Ankara | Sun     |              6 |           3 |          |
|  6 | 06.08.2018 00:00:00 | Ankara | Sun     |              5 |           3 |          |
|  7 | 05.08.2018 00:00:00 | Ankara | Rain    |              2 |           3 |          |
|  8 | 04.08.2018 00:00:00 | Ankara | Clouds  |              0 |           3 |          |
|  9 | 03.08.2018 00:00:00 | Ankara | Rain    |              0 |           2 |          |
| 10 | 02.08.2018 00:00:00 | Ankara | Sun     |              1 |           0 |          |
| 11 | 01.08.2018 00:00:00 | Ankara | Sun     |              0 |           0 |          |
| 12 | 11.08.2018 00:00:00 | Cairo  | Clouds  |              6 |           6 |          |
| 13 | 10.08.2018 00:00:00 | Cairo  | Sun     |              7 |           1 |          |
| 14 | 09.08.2018 00:00:00 | Cairo  | Sun     |              7 |           1 |          |
| 15 | 08.08.2018 00:00:00 | Cairo  | Sun     |              7 |           1 |          |
| 16 | 07.08.2018 00:00:00 | Cairo  | Sun     |              6 |           1 |          |
| 17 | 06.08.2018 00:00:00 | Cairo  | Sun     |              5 |           1 |          |
| 18 | 05.08.2018 00:00:00 | Cairo  | Clouds  |              0 |           4 |          |
| 19 | 04.08.2018 00:00:00 | Cairo  | Sun     |              3 |           0 |          |
| 20 | 03.08.2018 00:00:00 | Cairo  | Sun     |              2 |           0 |          |
| 21 | 02.08.2018 00:00:00 | Cairo  | Sun     |              1 |           0 |          |
| 22 | 01.08.2018 00:00:00 | Cairo  | Sun     |              0 |           0 |          |
+----+---------------------+--------+---------+----------------+-------------+----------+

您在不止一个问题上扩展了您的要求。我可以建议您考虑以上内容并决定是否可以使用这 2 个计算来得出想要的最终结果。如果您仍然无法得出结论,请使用文本 table 格式将 "expected result" 作为新列包含在内