asp.net - 从 select 语句更新多行

Question

我正在尝试根据此 SELECT 语句将“A”分配给 [Student Details].group。

SELECT     TOP (10) PERCENT [Person Id], [Given Names], Surname, Gpa, [Location Cd]
FROM         [Student Details]
WHERE     ([Location Cd] = 'PAR')
ORDER BY Gpa DESC

我不知道如何在 UPDATE 语句中使用 SELECT 语句。有人可以解释一下如何做到这一点吗？

我正在使用 ASP .NET 和 MsSQL Server，如果它有所作为的话。

谢谢

Answer 1

我假设您要更新这些记录，然后返回它们：

SELECT TOP (10) PERCENT [Person Id], [Given Names], Surname, Gpa, [Location Cd]
INTO #temp
FROM [Student Details]
WHERE     ([Location Cd] = 'PAR')
ORDER BY Gpa DESC

update [Student Details] set group='A' where [person id] in(select [person id] from #temp)

select * from #temp

我还假设人员 ID 是学生详细信息的 PK

Answer 2

这是你想要的吗？

Update top (10) Percent [Student Details] set [group] = 'A' 
where [Location Cd] = 'PAR' AND [group] is null

Answer 3

CTE使用（公用表表达式）试试这个：

;WITH CTE AS
(
    SELECT TOP 10 PERCENT [Group]
    FROM      [Student Details]
    WHERE     ([Location Cd] = 'PAR')
    ORDER BY Gpa DESC
)
UPDATE CTE SET [Group] = 'A'