Linq to Entities - 子查询在where语句中 [英] Linq to Entities - Subquery in the where statement

问题描述

这一定很简单，但是我一直在寻找2个小时，找不到答案。如何在Linq中写入这个实体：

This must be simple, but I've been searching for 2 hours, and can't find an answer. How do I write this in Linq to Entities:

SELECT Reg4, Reg5, Reg6
FROM dbo.Table1
WHERE Reg1 = 15
AND Reg2 = ( SELECT MAX(Reg2) FROM dbo.Table2 WHERE Reg1 = 15);

是否可以在查询表达式和基于方法的语法中执行此操作？

Tks

Is it possible to do it both in query expressions and method based syntaxes?
Tks

推荐答案

var r1 = 15;
var q = from t in Context.Table1
        where t.Reg1 == r1 && 
              t.Reg2 == Context.Table2
                               .Where(t2 => t2.Reg1 == r1)
                               .Max(t2 => t2.Reg2)
        select t;

如果您有从Table1到Table2的导航/关联，则更容易。但是你没有表现出来，所以我也不会....

Easier still if you have a navigation/association from Table1 to Table2. But you didn't show that, so neither will I....

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