如果在SQL Server中只有序列形式，我想计算名称列中的值[重复]

Posted 2021-04-20

这个问题在这里已有答案：

• Count Number of Consecutive Occurrence of values in Table 2回答

create table #t (Id int, Name nvarchar(max))    

insert into #t 
values (1, 'ABC'), (2, 'ABC'), (3, 'BBB'), (4, 'BBB'),  
       (5, 'BBB'), (6, 'BBB'), (7, 'CCC'), (8, 'BBB'),  
       (9, 'BBB'), (10, 'ABC')

我想计算名称列中的值，如果只有顺序形式我如何得到这个结果，如下表所示：

| Name | Repetition |   
('ABC'),    2
('ABC'),    2
('BBB'),    4
('BBB'),    4
('BBB'),    4
('BBB'),    4
('CCC'),    1
('BBB'),    2
('BBB'),    2
('ABC'),    1

答案

您还可以尝试间隙和岛类型方法来计算连续行，如下所示

See live demo

select 
    Name, 
    Repetition= count(1) over(  partition by r,Name )
from 
(
    select 
    *, 
    r=id-row_number() over(partition by Name order by Id) 
    from #t
 ) t
order by id

另一答案

试试这个多重cte解决方案：

;with name_change as (
  select *, case when name=lag(name, 1) over (order by id) then 0 else 1 end as indicator 
  from t
), name_group as (
  select name, sum(indicator) over (order by id) as g 
  from name_change
)
select name, count(name) over (partition by g) from name_group

虽然不确定效率，但我认为它能满足您的需求......

SQLFiddle