blocks|key|869162|text|使用Rails+3实现这一点的规范方法是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|869163|Foo.includes(:bar).where("bars.id+IS+NOT+NULL")|code-block|syntax|javascript|869164|ActiveRecord+4.0及更高版本添加了where.not，因此您可以执行以下操作：|offset|length|style|CODE|869165|Foo.includes(:bar).where.not('bars.id'+=>+nil)
Foo.includes(:bar).where.not(bars:+{+id:+nil+})|869166|在处理表之间的作用域时，我更喜欢利用merge，这样就可以更容易地使用现有作用域。|869167|Foo.includes(:bar).merge(Bar.where.not(id:+nil))|869168|此外，由于includes并不总是选择连接策略，因此在这里也应该使用references，否则可能会得到无效的SQL。|869169|Foo.includes(:bar)
+++.references(:bar)
+++.merge(Bar.where.not(id:+nil))|869170|entityMap|0|LINK|mutability|MUTABLE|url|http://edgeguides.rubyonrails.org/active_record_querying.html#not-conditions|1|http://api.rubyonrails.org/classes/ActiveRecord/SpawnMethods.html#method-i-merge|2|http://api.rubyonrails.org/classes/ActiveRecord/QueryMethods.html#method-i-includes|3|http://api.rubyonrails.org/classes/ActiveRecord/QueryMethods.html#method-i-references^0|0|0|O|9|O|9|0|0|0|I|5|I|5|1|0|0|5|8|Y|A|5|8|2|Y|A|3|0|0^^$0|@$1|2|3|4|5|6|7|1A|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|1B|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|1C|8|@$I|1D|J|1E|K|L]]|9|@$I|1F|J|1G|1|1H]]|A|$]]|$1|M|3|N|5|D|7|1I|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|1J|8|@$I|1K|J|1L|K|L]]|9|@$I|1M|J|1N|1|1O]]|A|$]]|$1|Q|3|R|5|D|7|1P|8|@]|9|@]|A|$E|F]]|$1|S|3|T|5|6|7|1Q|8|@$I|1R|J|1S|K|L]|$I|1T|J|1U|K|L]]|9|@$I|1V|J|1W|1|1X]|$I|1Y|J|1Z|1|20]]|A|$]]|$1|U|3|V|5|D|7|21|8|@]|9|@]|A|$E|F]]|$1|W|3|-4|5|6|7|22|8|@]|9|@]|A|$]]]|X|$Y|$5|Z|10|11|A|$12|13]]|14|$5|Z|10|11|A|$12|15]]|16|$5|Z|10|11|A|$12|17]]|18|$5|Z|10|11|A|$12|19]]]]

The canonical way to do this with Rails 3:

<pre><code>Foo.includes(:bar).where("bars.id IS NOT NULL")
</code></pre>

ActiveRecord 4.0 and above adds <a href="http://edgeguides.rubyonrails.org/active_record_querying.html#not-conditions" rel="noreferrer"><code>where.not</code></a> so you can do this:

<pre><code>Foo.includes(:bar).where.not('bars.id' =&gt; nil)
Foo.includes(:bar).where.not(bars: { id: nil })
</code></pre>

When working with scopes between tables, I prefer to leverage <a href="http://api.rubyonrails.org/classes/ActiveRecord/SpawnMethods.html#method-i-merge" rel="noreferrer"><code>merge</code></a> so that I can use existing scopes more easily.

<pre><code>Foo.includes(:bar).merge(Bar.where.not(id: nil))
</code></pre>

Also, since <a href="http://api.rubyonrails.org/classes/ActiveRecord/QueryMethods.html#method-i-includes" rel="noreferrer"><code>includes</code></a> does not always choose a join strategy, you should use <a href="http://api.rubyonrails.org/classes/ActiveRecord/QueryMethods.html#method-i-references" rel="noreferrer"><code>references</code></a> here as well, otherwise you may end up with invalid SQL.

<pre><code>Foo.includes(:bar)
 .references(:bar)
 .merge(Bar.where.not(id: nil))
</code></pre>

blocks|key|1083959|text|这不是ARel中的bug，而是您的逻辑中的bug。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1083960|您在这里需要的是：|1083961|Foo.includes(:bar).where(Bar.arel_table[:id].not_eq(nil))|code-block|syntax|javascript|1083962|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

It's not a bug in ARel, it's a bug in your logic.

What you want here is:

<pre><code>Foo.includes(:bar).where(Bar.arel_table[:id].not_eq(nil))
</code></pre>

blocks|key|1083982|text|使用Rails+4很容易：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1083983|+Foo.includes(:bar).where.not(bars:+{id:+nil})|code-block|syntax|javascript|1083984|另请参阅：http://guides.rubyonrails.org/active_record_querying.html#not-conditions|offset|length|1083985|entityMap|0|LINK|mutability|MUTABLE|url|http://guides.rubyonrails.org/active_record_querying.html#not-conditions^0|0|0|5|20|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

With Rails 4 it's easy:

<pre><code> Foo.includes(:bar).where.not(bars: {id: nil})
</code></pre>

See also: 
 <a href="http://guides.rubyonrails.org/active_record_querying.html#not-conditions">http://guides.rubyonrails.org/active_record_querying.html#not-conditions</a>

blocks|key|1084039|text|我不确定这是否有帮助，但这对我在Rails4中是有效的|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1084040|Foo.where.not(bar:+nil)|code-block|syntax|javascript|1084041|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|$]]

Not sure of this is helpful but this what worked for me in Rails 4

<pre><code>Foo.where.not(bar: nil)
</code></pre>

Using the rails 3 style how would I write the opposite of:

<pre><code>Foo.includes(:bar).where(:bars=&gt;{:id=&gt;nil})
</code></pre>

I want to find where id is NOT nil. I tried:

<pre><code>Foo.includes(:bar).where(:bars=&gt;{:id=&gt;!nil}).to_sql
</code></pre>

But that returns:

<pre><code>=&gt; "SELECT \"foos\".* FROM \"foos\" WHERE (\"bars\".\"id\" = 1)"
</code></pre>

That's definitely not what I need, and almost seems like a bug in ARel.

Rails where condition using NOT NIL

使用rails 3样式时，我该如何编写与以下内容相反的代码：Foo.includes(:bar).where(:bars=>{:id=>nil})我想找出id不为零的地方。我试过了：Foo.includes(:bar).where(:bars=>{:id=>!nil}).to_sql但这会得到回报：=> "SELECT...

问Rails where条件使用NOT NIL
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问Rails where条件使用NOT NILEN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问Rails where条件使用NOT NIL
EN