如何在sql中为记录添加计数

Question

我想在我的数据中为特定列添加一个数字：但是我的@id是静态的并且不会改变，我想念的是什么//这就是我需要的

names
-----
david1
david2
david3

//那是我的代码

 DECLARE @var INT 
SET @var = 0 
update [dbo].[ContactBase]
set FirstName = 'david  + convert(varchar(10),@var )    
set  @var =@var + 1;

Answer 1

看看下面的内容。

;
WITH    CTE
          AS (SELECT    FirstName
              ,         ROW_NUMBER() OVER (ORDER BY (SELECT 1
                                                    )) RN
              FROM      ContactBase
             )
    SELECT  *
    FROM    CTE

;
WITH    CTE
          AS (SELECT    FirstName
              ,         ROW_NUMBER() OVER (ORDER BY (SELECT 1
                                                    )) RN
              FROM      ContactBase
             )
    UPDATE CTE
    SET FirstName = FirstName + CAST(RN AS VARCHAR(10))

第一个调用只显示cte的输出，第二个实际处理更新。

同样使用行号选项，你也可以通过名称分隔出来，简单地给你david1，david2，Jon1，Jon2等。是一种重复数据删除的便捷方式。

DECLARE @ContactBase AS TABLE (FirstName VARCHAR(10))
INSERT INTO @ContactBase
        (FirstName)
VALUES  ('David'),('David'),('David')

SELECT * FROM @ContactBase

;WITH    CTE
          AS (SELECT    FirstName
              ,         ROW_NUMBER() OVER (ORDER BY (SELECT 1
                                                    )) RN
              FROM      @ContactBase
             )
    UPDATE CTE
    SET FirstName = FirstName + CAST(RN AS VARCHAR(10))

    SELECT * FROM @ContactBase

Answer 2

我不明白你想要什么......你想要

• 在FirstName的末尾添加一个数字（id）？
• 做一个循环谁用新id在你的数据库中添加元素？

Answer 3

使用ROW_NUMBER生成数字。

update n 
set firstname = 'david' + cast(num as varchar(10))
from
 (select firstname, row_number() over (order by firstname) as num from dbo.contactbase) n;

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