如何在SQL中使用变量或引用?

因为您需要整个数据库中每个用户以及每个帖子的计数,所以只需以简单的方式进行:

SELECT
    Id AS [User Link],
    Reputation,
    Reputation * 1.0 / C.Cnt AS [Rep Per Post]
FROM
   Users U
   INNER JOIN (
      SELECT OwnerUserId, Cnt = Count(*)
      FROM posts
      GROUP BY OwnerUserID
      HAVING Count(*) >= ##MinNumberOfPosts##
   ) C ON U.Id = C.OwnerUserId
ORDER BY [Rep Per Post] DESC

我补充道 * 1.0 因为我猜(不确定这里的引擎)整数除法产生整数,看起来你可能想要分数。你得做个实验。

你可以用 CROSS APPLY

DECLARE @MinPosts int = ##MinNumberOfPosts##

SELECT
    Id AS [User Link],
    Reputation,
    counts.[# Posts],
    Reputation / counts.[# Posts] AS [Rep Per Post]
FROM Users
  CROSS APPLY (
    SELECT COUNT(*)
    FROM posts
    WHERE posts.OwnerUserId = Users.Id
  ) counts([# Posts])
WHERE counts.[# Posts] > @MinPosts
ORDER BY [Rep Per Post] DESC​