创建rank（）或row_number（）列

Question

我有如下表格，

如果我们检查“n”列，它的双倍 - 如果问题重复，则用ansSecID分隔多个答案。

QuestionId + AnsSecId = unique row

我可以为“n”创建rank()列吗？ e.g. n = 8, has 2 rows. So i want 8_1, 8_2.

或

for n = 17, can I get 17_1,17_2,17_3

或类似rank()列。 some 1,2,3 row no。 ˚For repetitive n.

最多1个问题将是3个答案。

Answer 1

这样的事情：

select (cast(n as varchar(255)) +
        (case when count(*) over (partition by n) > 1
              then '_' + cast(row_number() over (partition by n order by anssecid) as varchar(255))
              else ''
         end)
        ) as new_n

实际上，您的repeat列似乎为when做了工作：

select (cast(n as varchar(255)) +
        (case when repeat > 0
              then '_' + cast(row_number() over (partition by n order by anssecid) as varchar(255))
              else ''
         end)
        ) as new_n

Answer 2

试试这个，我不在电脑上，但这应该有效。也可以使用n作为分区

select Cast (n as varchar)+'-'+cast (r as varchar) str
from (
     Select n, row_number() over (partition by q_id order by anssecid) r
     from table
     ) x