Question

目前，为了获得带有连接的复杂查询中的项目计数，我正在做这样的事情 -

string q = @"SELECT f.FILE_ID
           FROM [Email.Link] AS l INNER JOIN Email AS e ON (l.EMAIL_ID = e.EMAIL_ID)
           INNER JOIN File AS f ON (e.EMAIL_ID = f.EMAIL_ID)
           WHERE l.EntityId = 123";

var files = Context.ExecuteQuery<File>(q);
return files.Count();

任何更好的方法来做到这一点，而不是让所有的ID都回来计算？我更愿意做一个SELECT Count(*)并在linq中获得int。

Answer 1

您可以将准备好的FILE_ID作为SQL查询的一部分返回，而不是返回COUNT集合：

        string q = @"SELECT COUNT(f.FILE_ID)
        FROM [Email.Link] AS l INNER JOIN Email AS e ON (l.EMAIL_ID = e.EMAIL_ID)
        INNER JOIN File AS f ON (e.EMAIL_ID = f.EMAIL_ID)
        WHERE l.EntityId = 123";

       return Context.ExecuteQuery<Int32>(q);

Answer 2

试试这个

    string q = @"SELECT COUNT(f.FILE_ID)
    FROM [Email.Link] AS l INNER JOIN Email AS e ON (l.EMAIL_ID = e.EMAIL_ID)
    INNER JOIN File AS f ON (e.EMAIL_ID = f.EMAIL_ID)
    WHERE l.EntityId = 123";

   return Context.ExecuteQuery<Int32>(q).FirstOrDefault();

linq2sql - 如何使用原始SQL从DB获取计数？

2 个答案: