blocks|key|1732357|text|++++++++using+(DataContext+dc+=+new+DataContext())
++++++++{
++++++++++++var+q+=+from+t+in+dc.TableTests
++++++++++++++++++++group+t+by+t.SerialNumber
++++++++++++++++++++++++into+g
++++++++++++++++++++++++select+new
++++++++++++++++++++++++{
++++++++++++++++++++++++++++SerialNumber+=+g.Key,
++++++++++++++++++++++++++++uid+=+(from+t2+in+g+select+t2.uid).Max()
++++++++++++++++++++++++};
++++++++}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1732358|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code> using (DataContext dc = new DataContext())
 {
 var q = from t in dc.TableTests
 group t by t.SerialNumber
 into g
 select new
 {
 SerialNumber = g.Key,
 uid = (from t2 in g select t2.uid).Max()
 };
 }
</code></pre>

blocks|key|1732401|text|var+q+=+from+s+in+db.Serials
++++++++group+s+by+s.Serial_Number+into+g
++++++++select+new+{Serial_Number+=+g.Key,+MaxUid+=+g.Max(s+=>+s.uid)+}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1732402|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>var q = from s in db.Serials
 group s by s.Serial_Number into g
 select new {Serial_Number = g.Key, MaxUid = g.Max(s =&gt; s.uid) }
</code></pre>

blocks|key|1732492|text|我已经在LinqPad中检查了达米安·G的答案。而不是|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1732493|g.Group.Max(s+=>+s.uid)|code-block|syntax|javascript|1732494|应该是|1732495|g.Max(s+=>+s.uid)|1732496|谢谢!|1732497|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

I've checked DamienG's answer in LinqPad.
Instead of 

<pre><code>g.Group.Max(s =&gt; s.uid)
</code></pre>

should be

<pre><code>g.Max(s =&gt; s.uid)
</code></pre>

Thank you!

blocks|key|1517517|text|在方法链形式中：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1517518|db.Serials.GroupBy(i+=>+i.Serial_Number).Select(g+=>+new
++++{
++++++++Serial_Number+=+g.Key,
++++++++uid+=+g.Max(row+=>+row.uid)
++++});|code-block|syntax|javascript|1517519|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

In methods chain form:

<pre><code>db.Serials.GroupBy(i =&gt; i.Serial_Number).Select(g =&gt; new
 {
 Serial_Number = g.Key,
 uid = g.Max(row =&gt; row.uid)
 });
</code></pre>

blocks|key|1517589|text|如果只需要这两个字段，答案是可以的，但对于更复杂的对象，这种方法可能会很有用：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1517590|from+x+in+db.Serials+
group+x+by+x.Serial_Number+into+g+
orderby+g.Key+
select+g.OrderByDescending(z+=>+z.uid)
.FirstOrDefault()|code-block|syntax|javascript|1517591|..。这将避免“选择新的”|1517592|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

The answers are OK if you only require those two fields, but for a more complex object, maybe this approach could be useful:

<pre><code>from x in db.Serials 
group x by x.Serial_Number into g 
orderby g.Key 
select g.OrderByDescending(z =&gt; z.uid)
.FirstOrDefault()
</code></pre>

... this will avoid the "select new"

blocks|key|1517636|text|这可以在LINQ+lamda表达式中使用GroupBy和SelectMany来完成|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1517637|var+groupByMax+=+list.GroupBy(x=>x.item1).SelectMany(y=>y.Where(z=>z.item2+==+y.Max(i=>i.item2)));|code-block|syntax|javascript|1517638|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This can be done using GroupBy and SelectMany in LINQ lamda expression
<pre><code>var groupByMax = list.GroupBy(x=&gt;x.item1).SelectMany(y=&gt;y.Where(z=&gt;z.item2 == y.Max(i=&gt;i.item2)));
</code></pre>

I am looking for a way in LINQ to match the follow SQL Query.

<pre><code>Select max(uid) as uid, Serial_Number from Table Group BY Serial_Number
</code></pre>

Really looking for some help on this one. The above query gets the max uid of each Serial Number because of the <code>Group By</code> Syntax.

How do I get the MAX row with a GROUP BY in LINQ query?

我正在寻找一种在LINQ中匹配以下SQL查询的方法。Select max(uid) as uid, Serial_Number from Table Group BY Serial_Number在这件事上真的需要一些帮助。由于Group By语法，上面的查询获取每个序列号的最大uid。

问如何在LINQ查询中获得带有GROUP BY的最大行数？
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