如何更新表中的n行？

I need to update the first N rows in a table meeting a condition.

我需要更新满足条件的表中的前N行。

I know I can do an Update Top N... but the problem is that N is in a @variable.

我知道我可以做一个Update Top N ...但问题是N在@variable中。

UPDATE TOP @N SET ... doesn't work.

更新顶部@N SET ...不起作用。

Is there a way to do this that I am just missing?

有没有办法做到这一点，我只是失踪？

No specific table definitions here because it doesn't matter what the columns are.. If I can do it for a one column table I can do it for my table.

这里没有特定的表定义，因为列是什么并不重要。如果我可以为一个列表执行此操作，我可以为我的表执行此操作。

2 个解决方案

#1

You need to use parens after TOP clause when you want to use a variable:

当你想使用变量时，你需要在TOP子句之后使用parens：

UPDATE TOP(@N) ...

#2

WITH    q AS
        (
        SELECT  TOP (@r) *
        FROM    mytable
        ORDER BY
                col1
        )
UPDATE  q
SET     co12 = @value

UPDATE TOP (@r) will work but it will update any @r rows in no particular order.

UPDATE TOP（@r）将起作用，但它将以任何特定顺序更新任何@r行。

From the documentation:

从文档：

The rows referenced in the TOP expression used with INSERT, UPDATE, or DELETE are not arranged in any order. TOP n returns n random rows.

与INSERT，UPDATE或DELETE一起使用的TOP表达式中引用的行不按任何顺序排列。 TOP n返回n个随机行。

#1