The $where provides greater flexibility, but requires that the database processes the JavaScript expression or function for each document in the collection. Query Operator Array all elemMatch (query) size Bitwise Query Operators. Use the $where operator to pass either a string containing a JavaScript expression or a full JavaScript function to the query system. Starting in MongoDB 6.0, the distinct command returns the same results for collections and views when using arrays. ![]() For instance, if a field has as its value 1, 1, 1, then distinct considers 1, 1, and 1 as separate values. Notice though, that the MongoDB official documentation remarks that although the $where operator is very flexible, from a performance point of view it is a bit lacking: If the value of the specified field is an array, distinct considers each element of the array as a separate value. Array Query Operators Array operators return data based on array conditions. We started with the simplest one: match an exact array.ĭb.movies.find( ) Perform operations on the grouped data to return a single result. For example, you can use aggregation pipelines to: Group values from multiple documents together. Therefore without further ado, we are going to see some examples about array searching/filtering. The Aggregation Pipeline Builder in MongoDB Compass lets you create aggregation pipelines to process documents from a collection or view and return computed results. Querying returns a subset of documents in a collection, from no documents at all to the entire collection. Querying arrays is by no means a difficult task, but it has some interesting features, so I though the topic would be better served in a post of its own. The find method is used to perform queries in MongoDB. As an example, you might only want to find the names of the mountains in the database. Oftentimes, you’ll only need information from a handful of fields. In the left navigation pane, select the samplemflix database. In all the examples so far, whenever you queried the peaks collection, MongoDB returned one or more full documents. ![]() For the database deployment that contains the sample data, click Browse Collections. When writting about querying in filtering a MongoDB collection and about how to search in string fields, we did not cover the topic of arrays. In the MongoDB Atlas UI, click Database in the sidebar.
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