mongodb - How to return documents where two fields have same value

Mongodb - How to return documents where two fields have same value

To return documents in MongoDB where two fields have the same value, you can use the $where operator or the $expr operator with the $eq operator. Here's an example using the $where operator:

db.yourCollection.find({ $where: function() { return this.field1 === this.field2; } });

In the above example:

  • yourCollection is the name of your collection.
  • field1 and field2 are the two fields you want to compare.

Alternatively, you can use the $expr operator along with the $eq operator:

db.yourCollection.find({ $expr: { $eq: ["$field1", "$field2"] } });

This query will return documents where field1 is equal to field2. Adjust the collection name and field names according to your specific case.

Examples

  1. "MongoDB find documents with matching fields"

    • Code Implementation:
      db.collection.find({ field1: { $eq: "$field2" } })
    • Description: Using the $eq operator to find documents where the value of field1 is equal to the value of field2.

  2. "MongoDB find documents with same value in two fields"

    • Code Implementation:
      db.collection.find({ $where: "this.field1 === this.field2" })
    • Description: Utilizing the $where clause to execute a JavaScript expression that checks if field1 is equal to field2.

  3. "MongoDB query for matching field values"

    • Code Implementation:
      db.collection.find({ $expr: { $eq: ["$field1", "$field2"] } })
    • Description: Using the $expr operator along with $eq to compare the values of field1 and field2 within the same document.

  4. "MongoDB find documents with identical fields"

    • Code Implementation:
      db.collection.find({ field1: { $eq: "$field2" } })
    • Description: Similar to the first example, using $eq to find documents where the value of field1 is equal to the value of field2.

  5. "MongoDB find documents with matching values in two fields"

    • Code Implementation:
      db.collection.find({ $expr: { $eq: ["$field1", "$field2"] } })
    • Description: Employing $expr and $eq to compare the values of field1 and field2 within the context of the same document.

  6. "MongoDB aggregation to match documents with same field values"

    • Code Implementation:
      db.collection.aggregate([ { $match: { field1: { $eq: "$field2" } } } ])
    • Description: Using the $match stage in the aggregation pipeline to filter documents where the value of field1 is equal to the value of field2.

  7. "MongoDB query to find documents with equal field values"

    • Code Implementation:
      db.collection.find({ field1: { $eq: "$field2" } })
    • Description: Another example of using $eq to filter documents where the value of field1 is equal to the value of field2.

  8. "MongoDB find documents with matching values in two fields using $eq"

    • Code Implementation:
      db.collection.find({ field1: { $eq: "$field2" } })
    • Description: Demonstrating the use of $eq to find documents where the value of field1 is equal to the value of field2.

  9. "MongoDB filter documents where two fields are equal"

    • Code Implementation:
      db.collection.find({ field1: { $eq: "$field2" } })
    • Description: Reiterating the use of $eq for filtering documents based on the equality of values in field1 and field2.

  10. "MongoDB query for documents with same field values in a subdocument"

    • Code Implementation:
      db.collection.find({ "subdocument.field1": { $eq: "$subdocument.field2" } })
    • Description: Extending the concept to subdocuments, using $eq to filter documents where the value of subdocument.field1 is equal to the value of subdocument.field2.

More Tags

styling google-cdn mongodb-atlas c#-2.0 ruby-on-rails xorg unity3d-2dtools cancellation-token react-hot-loader pid

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