How do I find duplicate records in MongoDB?

This particular query finds duplicate values in the field1 column. Simply change this value to change the field to look in….How to Find Duplicates in MongoDB

  1. Group all documents having the same value in field1.
  2. Match the groups that have more than one document.
  3. Project all groups that have more than one document.

How does MongoDB find duplicates in array?

You can find duplicate values within your MongoDB database using the aggregate method along with the $group and $match aggregation pipeline operators.

  1. Let’s see how to use the aggregate method in MongoDB.
  2. The aggregate function takes the parameter as an array of aggregation operators.

How do I find duplicate keys in SQL?

How to Find Duplicate Values in SQL

  1. Using the GROUP BY clause to group all rows by the target column(s) – i.e. the column(s) you want to check for duplicate values on.
  2. Using the COUNT function in the HAVING clause to check if any of the groups have more than 1 entry; those would be the duplicate values.

Does MongoDB allow duplicates?

To insert records in MongoDB and avoid duplicates, use “unique:true”. Let us first create a collection with documents.

How can I find duplicate files?

Let’s jump right in.

  1. Solution 1: Use Windows Views to Search for Duplicate Files.
  2. Solution 2: Sort Files with Explorer Details Pane to Detect Duplicate Files.
  3. Solution 3: Use Search Feature to Locate Duplicate Files.
  4. Solution 2: CCleaner.
  5. Solution 3: Remo Duplicate File Remover.
  6. Solution 4: Auslogics Duplicate File Finder.

How do I select duplicates in SQL?

To select duplicate values, you need to create groups of rows with the same values and then select the groups with counts greater than one. You can achieve that by using GROUP BY and a HAVING clause.

How do I remove duplicates in MongoDB aggregation?

While MongoDB supports an option to drop duplicates, dropDups, during index builds, this option forces the creation of a unique index by way of deleting data. If you use the dropDups option, MongoDB will create an index on the first occurrence of a value for a given key and then delete all subsequent values.

What is Upsert MongoDB?

In MongoDB, upsert is an option that is used for update operation e.g. update(), findAndModify(), etc. Or in other words, upsert is a combination of update and insert (update + insert = upsert).

How do I find and delete duplicate files?

Delete duplicate files

  1. On your Android device, open Files by Google .
  2. At the bottom, tap Clean .
  3. On the “Duplicate files” card, tap Select files.
  4. Select the files you want to delete.
  5. At the bottom, tap Delete .
  6. On the confirmation dialog, tap Delete .

How do I find duplicate files with different names?

How to find duplicate files with different names on Windows PC

  1. Download and install Cisdem Duplicate Finder.
  2. To find duplicate files in a folder, drag the folder into the software.
  3. Click Scan.
  4. When the scan is done, the results window will display all the found duplicate files, including those with different filenames.