Question

这是我的数据：

liza
liza
liza
alex
alex
alex
liza

我想更新此表，其中包含每个名称的每次出现的数据，如下所示：

liza    4
liza    4
liza    4
alex    3
alex    3
alex    3
liza    4

到目前为止，我有：

update table set column2=count(name) group by name

非常感谢你的帮助

Answer 1

update T1 set
  Column2 = T2.C
from YourTable as T1
  inner join (
                select count(*) as C, Name
                from YourTable
                group by Name
             ) as T2  
    on T1.Name = T2.Name

带有表变量的示例

declare @YourTable table 
(
  Name varchar(10),
  Column2 int
)

insert into @YourTable (Name) values
('liza'),('liza'),('liza'),('alex'),('alex'),('alex'),('liza')

update T1 set
  Column2 = T2.C
from @YourTable as T1
  inner join (
                select count(*) as C, Name
                from @YourTable
                group by Name
             ) as T2  
    on T1.Name = T2.Name

在这里试试。 http://data.stackexchange.com/stackoverflow/q/102392/update-with-count

以下是使用CTE和count(*) over()的另一种方式。

declare @YourTable table 
(
  Name varchar(10),
  Column2 int
)

insert into @YourTable (Name) values
('liza'),('liza'),('liza'),('alex'),('alex'),('alex'),('liza')

;with cte as
(
  select Column2,
         count(*) over(partition by Name) as C
  from @YourTable        
)
update cte set
  Column2 = C

这个查询你可以在这里试试。 http://data.stackexchange.com/stackoverflow/q/102394/update-with-count-2

用if子句或case进行sql server 2008查询？

1 个答案: