blocks|key|94056|text|您可以尝试以下代码。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|94057|Country::with(['states.cities.streets.houses'+=>+function+($query)+{
++++$query->select('bedrooms',+'...');
}])->sum('bedrooms');|code-block|syntax|javascript|94058|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|$]]

You can try the following code. 

<pre><code>Country::with(['states.cities.streets.houses' =&gt; function ($query) {
 $query-&gt;select('bedrooms', '...');
}])-&gt;sum('bedrooms');
</code></pre>

blocks|key|2830386|text|我目前正在使用State和City上的hasManyThrough来解决这个问题，然后：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2830387|$country->load('cities.houses');
echo+$country->cities->sum(function+($city)+{
++++++++++++++++++++return+$city->houses->sum('bedrooms');
++++++++++++++++});|code-block|syntax|javascript|2830388|但感觉还是不是很好。任何更好的答案都非常感谢。|2830389|entityMap^0|7|5|D|4|J|E|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|W|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|N|$]]

I am currently solving this using <code>hasManyThrough</code> on <code>State</code> and <code>City</code> and then:

<pre><code>$country-&gt;load('cities.houses');
echo $country-&gt;cities-&gt;sum(function ($city) {
 return $city-&gt;houses-&gt;sum('bedrooms');
 });
</code></pre>

But it still doesn't feel great. Any better answers much appreciated.

blocks|key|91813|text|如果你有很大的结果，你不应该在应用层中得到它们的总和。尝试使用SQL+Sum函数。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|91814|如果你想以雄辩的方式做到这一点，这应该是你最好的解决方案：|91815|Country::with(['states.cities.streets.houses'+=>+function+($query)+{
++++$query->select('bedrooms');
}])->sum('bedrooms');|code-block|syntax|javascript|91816|如果不是这样，就使用如下的DB查询：|91817|DB::table('countries')
++++->join('states',+'..',+'..')
++++->join('cities',+'..',+'..')
++++->join('streets',+'..',+'..')
++++->join('houses',+'..',+'..')
++++->selectRaw('SUM(bedrooms)+as+sum')
++++->pluck('sum')[0]|91818|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

If you have large result, You should not get sum of them in the application layer. Try to use SQL Sum function.

This should be your best solution if you want to do it in Eloquent way:

<pre><code>Country::with(['states.cities.streets.houses' =&gt; function ($query) {
 $query-&gt;select('bedrooms');
}])-&gt;sum('bedrooms');
</code></pre>

And if not use DB queries like this:

<pre><code>DB::table('countries')
 -&gt;join('states', '..', '..')
 -&gt;join('cities', '..', '..')
 -&gt;join('streets', '..', '..')
 -&gt;join('houses', '..', '..')
 -&gt;selectRaw('SUM(bedrooms) as sum')
 -&gt;pluck('sum')[0]
</code></pre>

blocks|key|94125|text|我创建了一个无限级别的HasManyThrough关系：Repository+on+GitHub|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|94126|安装完成后，您可以这样使用它：|94127|class+Country+extends+Model+{
++++use+\Staudenmeir\EloquentHasManyDeep\HasRelationships;

++++public+function+houses()+{
++++++++return+$this->hasManyDeep(House::class,+[State::class,+City::class,+Street::class]);
++++}
}

$sum+=+$country->houses()->sum('bedrooms');|code-block|syntax|javascript|94128|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/staudenmeir/eloquent-has-many-deep^0|B|E|S|K|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@$9|X|A|Y|1|Z]]|E|$]]|$1|F|3|G|5|6|7|10|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|11|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|12|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]]]

I created a <code>HasManyThrough</code> relationship with unlimited levels: <a href="https://github.com/staudenmeir/eloquent-has-many-deep" rel="nofollow noreferrer">Repository on GitHub</a>

After the installation, you can use it like this:



<pre class="lang-php prettyprint-override"><code>class Country extends Model {
 use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

 public function houses() {
 return $this-&gt;hasManyDeep(House::class, [State::class, City::class, Street::class]);
 }
}

$sum = $country-&gt;houses()-&gt;sum('bedrooms');
</code></pre>

I have a number of nested <code>hasMany</code> relations in Laravel 5.6. I am looking for an efficient way to sum an attribute on each of the outermost nodes of the relationships.

For example, each of these is linked by a <code>hasMany</code>.

<code>Country</code> -> <code>States</code> -> <code>Cities</code> -> <code>Streets</code> -> <code>Houses</code>

If I want to sum all the <code>House-&gt;bedrooms</code> in a given <code>Country</code>, what is the most efficient way?

At the moment I have an eager-Loaded <code>Country</code> in memory as follows:

<pre><code>$country-&gt;load('states.cities.streets.houses');
</code></pre>

And I tried:

<pre><code>$country-&gt;states-&gt;cities-&gt;streets-&gt;houses-&gt;pluck('bedrooms')-&gt;sum()
</code></pre>

But got:

<blockquote>
 Property [cities] does not exist on this collection instance.
</blockquote>

I could do this with <code>foreach</code> loops over the various relations but it feels like there must be a more code-efficient way built into Laravel. What am I missing?

Thanks

Laravel: Efficiently sum nested relations (eager loaded)

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我在Laravel5.6中有很多嵌套的hasMany关系。我正在寻找一种有效的方法来对关系的每个最外层节点上的属性进行求和。例如，其中的每一个都由hasMany链接。Country -> States -> Cities -> Streets -> Houses如果我想对给定Country中的所有House->bedr...

问Laravel:有效地求和嵌套关系(eager )
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