linq - LINQ - 从选择中计数，没有分组依据

Question

Linq 对我来说是全新的，所以如果这真的很愚蠢，我很抱歉。

我正在尝试从带有 where 子句的多表连接中获取计数，而不使用 group by。我已经看到了 group by 的示例，如果需要，我会使用它，但我想知道是否有办法避免它。是 sql 我的查询看起来像这样吗？

 SELECT Count(*)
FROM   plans p
       JOIN organizations o
         ON p.org_id = o.org_id
            AND o.deleted IS NULL
       JOIN orgdata od
         ON od.org_id = o.org_id
            AND od.active = 1
       JOIN orgsys os
         ON os.sys_id = od.sys_id
            AND os.deleted IS NULL
WHERE  p.deleted IS NULL
       AND os.name NOT IN ( 'xxxx', 'yyyy', 'zzzz' ) 

得到这个的最好方法是什么？

Answer 1

你只需要打电话Count()。你只计算结果的数量。所以像：

var names = new[] { "xxxx", "yyyy", "zzzz" };
var query = from plan in db.Plans
            where plan.Deleted == null
            join organization in db.Organizations
              on plan.OrganizationId equals organization.OrganizationId
            where organization.Deleted == null
            join orgData in db.OrganizationData
              on organization.OrganizationId equals orgData.OrganizationId
            where orgData.Active == 1
            join os on db.OrganizationSystems
              on orgData.SystemId equals os.SystemId
            where os.Deleted == null &&
                  !names.Contains(os.Name)
            select 1; // It doesn't matter what you select here
 var count = query.Count();