Sql server 正在更新ID不断增加的Sql Server行

如何根据另一列使用增加的ID更新sql server

我有一个具有以下结构的表：

sn  name    val
    test     0
    test     0.5
    test     2
    test1    0
    test1    0.5
    test1     2

我如何更新它，以便：

sn  name      val
1    test      0
2    test      0.5
3    test      2
1    test1     0
2    test1     0.5
3    test1     2

使用cte和行号

以下是一个例子：

create table #mytable (sn int, name varchar(20), val money)

insert into #mytable values (null, 'test', 0.5)
insert into #mytable values (null, 'test', 1)
insert into #mytable values (null, 'test1', 0.5)
insert into #mytable values (null, 'test1', 1)

;with cte as (select row_number() over (order by name, val) as rn, * from #mytable)
update cte set sn = rn

select * from #mytable

使用cte和行号

以下是一个例子：

create table #mytable (sn int, name varchar(20), val money)

insert into #mytable values (null, 'test', 0.5)
insert into #mytable values (null, 'test', 1)
insert into #mytable values (null, 'test1', 0.5)
insert into #mytable values (null, 'test1', 1)

;with cte as (select row_number() over (order by name, val) as rn, * from #mytable)
update cte set sn = rn

select * from #mytable

---

如果表中有键列，则可以使用和轻松完成此操作。我添加了一列：

Id int-identity主键

，下面是更新：

;with RowNumberedData as (
  select 
    id, 
    row_number() over (
      partition by name
      order by id
    ) as rowno
  from sql_test
)
update s
  set sn = r.rowno
from sql_test s
join RowNumberedData r
  on s.id = r.id;

---

SQLFIDLE:

如果表中有键列，则可以使用和轻松完成此操作。我添加了一列：

Id int-identity主键

，下面是更新：

;with RowNumberedData as (
  select 
    id, 
    row_number() over (
      partition by name
      order by id
    ) as rowno
  from sql_test
)
update s
  set sn = r.rowno
from sql_test s
join RowNumberedData r
  on s.id = r.id;

---

SQLFiddle:

您应该使用

行数（）

函数。此外，只要您必须为每个名称值启动新计数器，您就应该在此语句中使用

partton by NAME

WITH T AS 
(select sql_test.*,
        ROW_NUMBER() OVER (PARTITION BY Name ORDER BY Val) as RowNumber
        from sql_test)
UPDATE T SET SN=RowNumber;

---

您应该使用

行编号（）

函数。此外，只要您必须为每个名称值启动新计数器，您就应该在此语句中使用

partton by NAME

WITH T AS 
(select sql_test.*,
        ROW_NUMBER() OVER (PARTITION BY Name ORDER BY Val) as RowNumber
        from sql_test)
UPDATE T SET SN=RowNumber;

---

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