Find Documents using AND and OR Condition
Overview
MongoDB is a popular NoSQL database used in modern web applications for its flexibility and scalability. We can find documents using AND and OR condition in MongoDB using AND operator and OR operator along with the find() method. The AND operator is used with the find() method to retrieve the documents that satisfy all the given criteria simultaneously. The OR operator is used with the find() method to retrieve documents that satisfy at least one of the given criteria. MongoDB Find Documents using AND and OR Condition can help us write complex queries to efficiently retrieve specific data from MongoDB.
Introduction
We can find documents using AND and OR Condition in MongoDB. Using the AND operator, we can combine two or more conditions to filter our data more precisely. It can combine multiple conditions in a single query by using logical AND. It can be used with the find() method to retrieve documents that match all the designated criteria.
By using the OR operator, we can combine multiple conditions in a single query by using logical OR. It can be used with the find() method to retrieve documents that match at least one of the specified criteria.
When working with MongoDB, mastering the use of logical operators like AND and OR is crucial to efficiently find documents that meet specific criteria, which is why knowing how to perform MongoDB Find Documents using AND and OR Condition is essential for developers.
In this article, we will explore how to Find Documents using AND and OR Condition in MongoDB.
What is the Find Method in MongoDB?
The "find()" method in MongoDB is a very significant and effective tool for querying data from a MongoDB database. It retrieves documents that match the criteria we specify. The method returns a cursor object, which can be used to loop through the matching documents and perform additional analysis or processing. We can also specify which fields to include or exclude in the results.
Syntax
| Parameter | Type | Description |
|---|---|---|
| query | document | (Optional) It is used to specify the search criteria using query operators for selecting documents from a collection. We can remove this parameter or pass an empty document ({}), to return all documents in the collection. |
| projection | document | (Optional) It specifies which fields should be returned in documents that match the query filter. We should remove this parameter if we want to return all the fields of the documents which match the specified filter. |
| options | document | (Optional) It specifies additional query options. |
We can understand the "find() method" better with the help of some examples.
Example 1:
We have six documents in the "movies" collection.
Syntax:
We can see that we retrieved all the six documents present in the "movies" collection after using the "find() method", without any parameter.
Example 2:
We can also specify the criteria based on which we can find a document.
We want to find all the documents which have the title = "Troll".
Syntax:
Since there is only one document present in the "movies" collection with the title = "Troll", that document is returned, as shown in the above image.
The findOne() Method
We also have the findOne() method in MongoDB. This method is used to find the first document in the collection that matches the specified criteria. If there are no documents matching the specified filter, it returns NULL.
To gain a better understanding of how the findOne() method works, let us see an example.
Example 3:
We insert another document in the "movies" collection.
The document is:
Thus now we have seven documents in the "movies" collection.
If we use the find() method for finding all the documents with title = "Black Adam", two documents are returned, as shown in the image below.
Syntax:
Whereas, on using the findOne() method to find a document with title = "Black Adam", only 1 document, that is, the first document with the title = "Black Adam" is returned. It has been shown in the image given below.
Syntax:
What is AND in MongoDB?
When searching for specific data in a collection, the $and operator in MongoDB allows us to combine various search conditions. It returns only the documents that satisfy every criterion that has been specified. The AND operator is used to retrieve documents that match multiple criteria simultaneously, and it is very useful when we need to search for documents that meet numerous requirements at once. For a document to be included in the result set when using the AND operator, all of the conditions specified must be true.
Syntax
$and operator performs a logical AND operation on an array of one or more than one expression (<expression1>, <expression2>, ..., <expressionN>). It returns the documents that satisfy all the expressions.
What is OR in MongoDB?
When searching for specific data in a collection, the $or operator in MongoDB enables us to combine multiple search conditions by performing a logical OR operation. It returns the documents that satisfy any of the criteria that have been specified. The OR operator is helpful when we want to find documents that match any of the given conditions instead of requiring all of them to be met simultaneously. For a document to be included in the result set when using the OR operator, at least one of the conditions specified must be true. This provides greater flexibility in querying data and allows for more efficient searching of large collections.
Syntax
$or operator performs a logical OR operation on an array of one or more than one expression (<expression1>, <expression2>, ..., <expressionN>). It returns the documents that satisfy at least one of the expressions.
How to Use the AND Method to Find Documents?
As we have discussed before, the AND operator is used to retrieve documents that match all the specified conditions. So we can use the AND operator along with the find() method to narrow down the search and return all the documents in the collection which match the specified criteria at once.
Syntax
Here, the find() method finds and returns documents from the "collection", after performing logical AND operation on one or more than one expressions (<expression1>, <expression2>, ..., <expressionN>). The documents returned match all of the specified expressions.
Let us understand how we can use AND method to find documents with the help of some examples:
Example 1: Now, we want to show all the documents with the releaseDate = "2022-10-19" and the title = "Black Adam".
Syntax
Therefore, two documents that match both the specified criteria are returned.
Example 2: Now, we want to show all the documents with the imdbId = "tt6443346" and the title = "Black Adam".
Syntax
Therefore, we can see that only one document has been returned because there are two documents that have the title = "Black Adam", but only one of them has the imdbId = "tt6443346". Thus we can see that the AND operator returns documents that satisfy all the specified conditions.
How to Use OR Method to Find Documents?
As we have discussed before, the OR operator is used to retrieve documents that match at least one of the specified conditions. So we can use the OR operator along with the find() method to return all the documents in the collection which match at least one of the specified criteria.
Syntax
Here, the find() method finds and returns documents from the "collection", after performing logical OR operation on one or more than one expression (<expression1>, <expression2>, ..., <expressionN>). The documents returned match at least one of the specified expressions.
Let us understand how we can use OR method to find documents with the help of some examples:
Example 1: We want to show all the documents with the imdbId = "tt3447590" or with the title = "Black Adam".
Syntax
Therefore, three documents are returned. One document has the imdbId = "tt3447590" and two documents have the title = "Black Adam".
Example 2: We want to show all the documents with the releaseDate = "2009-12-15" or with the title = "Troll".
Syntax
Therefore, we can see that two documents have been returned. One document has releaseDate = "2009-12-15", another document has title = "Troll". Thus we can see that the OR operator returns documents that satisfy at least one of the specified conditions.
Conclusion
- The find() method is used for retrieving documents according to the specified conditions. It returns all the documents that match the given conditions. If no condition has been provided, then it retrieves all the documents present in the collection.
- The findOne() method in MongoDB is used to search a collection and retrieve the first document that meets the specified search criteria, even if multiple documents match those criteria. This method stops searching once it finds a matching document and returns only that document.
- The AND operator in MongoDB combines various search conditions and returns only the documents that satisfy every specified criterion.
- The OR operator in MongoDB combines multiple search conditions by performing a logical OR operation and returns the documents that satisfy any of the specified criteria.
- We can use the find() method with the AND operator to retrieve documents that match all the specified criteria at once.
- We can use the find() method with the OR operator to retrieve documents that match at least one of the specified criteria.
- We have explored how to Find Documents using AND and OR Condition in MongoDB.