如果在 Microsoft tSQL 中找不到任何行，则返回一个值 [英] Return a value if no rows are found in Microsoft tSQL

问题描述

使用 Microsoft 版本的 SQL，这是我的简单查询.如果我查询不存在的记录，则不会返回任何内容.我更喜欢在这种情况下返回 false (0).寻找最简单的方法来说明没有记录.

Using a Microsoft version of SQL, here's my simple query. If I query a record that doesn't exist then I will get nothing returned. I'd prefer that false (0) is returned in that scenario. Looking for the simplest method to account for no records.

SELECT  CASE
            WHEN S.Id IS NOT NULL AND S.Status = 1 AND (S.WebUserId = @WebUserId OR S.AllowUploads = 1) THEN 1
            ELSE 0
        END AS [Value]

        FROM Sites S

        WHERE S.Id = @SiteId

推荐答案

SELECT CASE WHEN COUNT(1) > 0 THEN 1 ELSE 0 END AS [Value]

FROM Sites S

WHERE S.Id = @SiteId and S.Status = 1 AND 
      (S.WebUserId = @WebUserId OR S.AllowUploads = 1)

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