在Oracle中为以下数据编写查询时，我需要帮助。数据按“人”和“天”字段排序。
Person Day Flag
------ --- ----
person1 day1 Y
person1 day2 Y
person1 day3 Y
person1 day4 N
person1 day5 N
person1 day6 Y
person1 day7 Y
person1 day8 Y
我需要有一个Group_Number列，每当Flag值更改时，该列都会增加。我的结果应该如下所示
Person Day Flag Group_Number
------ --- ---- ------------
person1 day1 Y 1
person1 day2 Y 1
person1 day3 Y 1
person1 day4 N 2
person1 day5 N 2
person1 day6 Y 3
person1 day7 Y 3
person1 day8 Y 3
我认为可以使用ROW_NUMBER，LEAD等分析功能来获得以上结果。
最佳答案
您可以将analytic functions SUM(用作运行总计)和 LAG 结合使用:
SQL> WITH data AS (
2 SELECT 'person1' person, 'day1' day, 'Y' flag FROM dual
3 UNION ALL SELECT 'person1' person, 'day2' day, 'Y' flag FROM dual
4 UNION ALL SELECT 'person1' person, 'day3' day, 'Y' flag FROM dual
5 UNION ALL SELECT 'person1' person, 'day4' day, 'N' flag FROM dual
6 UNION ALL SELECT 'person1' person, 'day5' day, 'N' flag FROM dual
7 UNION ALL SELECT 'person1' person, 'day6' day, 'Y' flag FROM dual
8 UNION ALL SELECT 'person1' person, 'day7' day, 'Y' flag FROM dual
9 UNION ALL SELECT 'person1' person, 'day8' day, 'Y' flag FROM dual
10 )
11 SELECT person, DAY, flag, SUM(gap) over (PARTITION BY person
12 ORDER BY DAY) grp
13 FROM (SELECT person, DAY, flag,
14 CASE WHEN flag = lag(flag) over (PARTITION BY person
15 ORDER BY DAY)
16 THEN 0
17 ELSE 1
18 END gap
19 FROM DATA);
PERSON DAY FLAG GRP
------- ---- ---- ----------
person1 day1 Y 1
person1 day2 Y 1
person1 day3 Y 1
person1 day4 N 2
person1 day5 N 2
person1 day6 Y 3
person1 day7 Y 3
person1 day8 Y 3
关于oracle - 在Oracle中字段值更改时增加行号，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/16563581/