查找包含特定值的数组的文档

本文翻译自&＃xff1a;Find document with array that contains a specific value

If I have this schema... 如果我有这个架构...

person &＃61; {name : String,favoriteFoods : Array
}


... where the favoriteFoods array is populated with strings. ...在字符串中填充favoriteFoods数组。 How can I find all persons that have "sushi" as their favorite food using mongoose? 我怎样才能找到所有以猫鼬为食的人&＃xff1f;

I was hoping for something along the lines of: 我一直希望以下方面的东西&＃xff1a;

PersonModel.find({ favoriteFoods : { $contains : "sushi" }, function(...) {...});


(I know that there is no $contains in mongodb, just explaining what I was expecting to find before knowing the solution) &＃xff08;我知道mongodb中没有$contains &＃xff0c;只是在知道解决方案之前先解释了我期望找到的内容&＃xff09;

#1楼

参考&＃xff1a;https://stackoom.com/question/1E9AM/查找包含特定值的数组的文档

#2楼

As favouriteFoods is a simple array of strings, you can just query that field directly: 由于favouriteFoods是一个简单的字符串数组&＃xff0c;因此您可以直接查询该字段&＃xff1a;

PersonModel.find({ favouriteFoods: "sushi" }, ...);


But I&＃39;d also recommend making the string array explicit in your schema: 但我也建议您在架构中使字符串数组显式&＃xff1a;

person &＃61; {name : String,favouriteFoods : [String]
}


The relevant documentation can be found here: https://docs.mongodb.com/manual/tutorial/query-arrays/ 相关文档可以在这里找到&＃xff1a; https : //docs.mongodb.com/manual/tutorial/query-arrays/

#3楼

There is no $contains operator in mongodb. mongodb中没有$contains运算符。

You can use the answer from JohnnyHK as that works. 您可以使用JohnnyHK的答案&＃xff0c;因为它可以起作用。 The closest analogy to contains that mongo has is $in , using this your query would look like: 包含mongo的最接近类推是$in &＃xff0c;使用此查询&＃xff0c;您的查询将类似于&＃xff1a;

PersonModel.find({ favouriteFoods: { "$in" : ["sushi"]} }, ...);


#4楼

I know this topic is old, but for future people who could wonder the same question, another incredibly inefficient solution could be to do: 我知道这个话题很老&＃xff0c;但是对于将来可能会想知道相同问题的人们&＃xff0c;另一种效率极低的解决方案是&＃xff1a;

PersonModel.find({$where : &＃39;this.favouriteFoods.indexOf("sushi") !&＃61; -1&＃39;});


This avoids all optimisations by MongoDB so do not use in production code. 这避免了MongoDB的所有优化&＃xff0c;因此请勿在生产代码中使用。

#5楼

In case you need to find documents which contain NULL elements inside an array of sub-documents, I&＃39;ve found this query which works pretty well: 如果您需要在子文档数组中查找包含NULL元素的文档&＃xff0c;我发现此查询非常有效&＃xff1a;

db.collection.find({"keyWithArray":{$elemMatch:{"$in":[null], "$exists":true}}})


This query is taken from this post: MongoDb query array with null values 该查询摘自该帖子&＃xff1a; 具有空值的MongoDb查询数组

It was a great find and it works much better than my own initial and wrong version (which turned out to work fine only for arrays with one element): 这是一个很好的发现&＃xff0c;它比我自己的初始版本和错误版本要好得多&＃xff08;原来的版本只适用于具有一个元素的数组&＃xff09;&＃xff1a;

.find({&＃39;MyArrayOfSubDocuments&＃39;: { $not: { $size: 0 } },&＃39;MyArrayOfSubDocuments._id&＃39;: { $exists: false }
})


#6楼

I feel like $all would be more appropriate in this situation. 我觉得$all在这种情况下会更合适。 If you are looking for person that is into sushi you do : 如果您正在寻找喜欢寿司的人&＃xff0c;可以这样做&＃xff1a;

PersonModel.find({ favoriteFood : { $all : ["sushi"] }, ...})


As you might want to filter more your search, like so : 您可能希望过滤更多搜索内容&＃xff0c;例如&＃xff1a;

PersonModel.find({ favoriteFood : { $all : ["sushi", "bananas"] }, ...})


$in is like OR and $all like AND. $in就像OR&＃xff0c; $all像AND。 Check this : https://docs.mongodb.com/manual/reference/operator/query/all/ 检查一下&＃xff1a; https : //docs.mongodb.com/manual/reference/operator/query/all/