sql中查找模式并计算有多少次出现

Question

数据给

22 
22 
22 
22 
22 
36 
54 
40 
22 
22 
22 
22 
36 
22 
22 
54 
22 
22 

这是在表中的列。使用SQL查询，我们需要找出图案如 22 36 54 40是第一图案然后22图36是第二和22 54是第三图案。

Answer 1

您应该使用LEAD来获取下一行的值，看看它是否是22，并使用它来摆脱列中所有额外的22。东西这种效果：

declare @t table (id int identity(1,1) not null, n int) 
insert into @t 
select 22 union all 
select 22 union all 
select 22 union all 
select 22 union all 
select 22 union all 
select 36 union all 
select 54 union all 
select 40 union all 
select 22 union all 
select 22 union all 
select 22 union all 
select 22 union all 
select 36 union all 
select 22 union all 
select 22 union all 
select 54 union all 
select 22 union all 
select 22 

select id,n from (select id,n ,lead(n) over (order by id) 
as lead_val from @t) t where n<>22 or lead_val<>22 

此输出：

5 22 
6 36 
7 54 
8 40 
12 22 
13 36 
15 22 
16 54 

Answer 2

的PostgreSQL

假设：

• 有确定所述元素的顺序的列
• 种所有模式与22

---

select  array_to_string(array_agg(val order by i),',') as pattern 
      ,min (i)          as from_i 
      ,max (i)          as to_i 
      ,count(*)          as pattern_length   

from  (select i,val 
        ,count(case when val = 22 then 1 end) over 
        (
         order by i 
         rows unbounded preceding 
        ) as pattern_id 

      from mytable 
      ) t 

group by pattern_id 

having  count(*)>1 
; 

---

+-------------+--------+------+----------------+ 
| pattern | from_i | to_i | pattern_length | 
+-------------+--------+------+----------------+ 
| 22,36,54,40 |  5 | 8 |    4 | 
| 22,36  |  12 | 13 |    2 | 
| 22,54  |  15 | 16 |    2 | 
+-------------+--------+------+----------------+