Question

我必须编写一个查询来查找3个或更多连续出现的值（引用列标志），它必须在连续的日期发生。如果连续日期没有发生，查询不应该选择值例如

COLUMN ID   DATE            FLAG
100         10-JUL-2015     Y
100         11-JUL-2015     Y
100         12-JUL-2015     Y
100         13-JUL-2015     N
100         14-JUL-2015     Y
100         15-JUL-2015     Y
100         16-JUL-2015     N
100         17-JUL-2015     Y
100         18-JUL-2015     Y
100         19-JUL-2015     Y
100         20-JUL-2015     Y
100         21-JUL-2015     Y

输出

COLUMN ID   DATE            FLAG
100         10-JUL-2015     Y
100         11-JUL-2015     Y
100         12-JUL-2015     Y
100         17-JUL-2015     Y
100         18-JUL-2015     Y
100         19-JUL-2015     Y
100         20-JUL-2015     Y
100         21-JUL-2015     Y

在Oracle SQL中完成此任务的任何想法。我正在尝试使用像LAG和LEAD这样的分析函数，但却无法实现这一目标。

Answer 1

你可以用一个非常方便的技巧来做到这一点。可以使用row_number() s的差来计算连续值组。然后，您需要获取每个组的计数并选择符合您条件的组：

select t.*
from (select t.*, count(*) over (partition by id, flag, grp) as cnt
      from (select t.*,
                   (row_number() over (partition by id order by date) -
                    row_number() over (partition by id, flag order by date)
                   ) as grp
            from table t
           ) t
     ) t
where cnt >= 3;

严格来说，您不需要row_numbers()的差异。假设您的日期没有时间组件，以下内容也足够了：

select t.*
from (select t.*, count(*) over (partition by id, flag, grp) as cnt
      from (select t.*,
                   (date -
                    row_number() over (partition by id, flag order by date)
                   ) as grp
            from table t
           ) t
     ) t
where cnt >= 3;

Answer 2

你可以试试这个。这使用了递归公用表表达式和lead分析函数。

with x as
(select id, mydate, flag from table1 where flag = 'Y')
, y as(select id, mydate, lead(mydate) over(order by mydate) as nxt,flag from x)
, z as (select id, mydate, nxt, lead(nxt) over(order by nxt) as nxt_1,flag from y)
select distinct t.id, t.mydate,t.flag from z
join x t on z.id = t.id 
and (t.mydate = z.mydate or t.mydate = z.nxt or t.mydate = z.nxt_1)
where z.nxt-z.mydate = 1 and z.nxt_1-z.nxt =1
order by t.mydate

SQL测试数据：http://sqlfiddle.com/#!4/9bbed/1

Oracle SQL - 在连续日期中查找连续值

2 个答案: