如何在按客户分组中放置计数器

How to put a counter in Group By Customer(如何在按客户分组中放置计数器)

问题描述

它们是同一列

Name-Category
A-SL
B-SL
C-SL
A-SL
A-SL
C-SL

现在在我的脚本中，我将它们分组到类别中，但我想计算它们在查询中出现的次数.请看下面:

now in my script, i group them in Category but i want to count on how many times they occur in the query. please see below:

Customer-Line#
A-1 (means its the first time it occurs)
A-2 (means its the second time it occurs)
A-3 (means its the third time it occurs)
....so on
----------
B-1 (means its the first time it occurs)
----------
C-1 (means its the first time it occurs)
C-2 (means its the second time it occurs)

抱歉造成混乱，希望大家都清楚.

sorry for confusion, hope its clear for everyone.

谢谢，

推荐答案

您可以使用 row_number() 给同名的客户添加一个数字:

You can use row_number() to add a number to customers with the same name:

select  name + '-' + cast(row_number() over (
            partition by name order by id) as varchar(24))
from    YourTable

如果只有在有多个客户时才需要号码，您可以使用 case when ... then ... end 表达式:

If the number is only required if there is more than one customer, you can use a case when ... then ... end expression:

select  name + 
            case 
            when count(*) over (partition by name) = 1 then ''
            else '-' + cast(row_number() over (
                partition by name order by id) as varchar(24))
            end
from    YourTable

SQL Fiddle 示例.

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