MongoDB query to search for string like "@email" in the field values

To search for strings containing "@email" in MongoDB field values, use regular expressions with the find() method. The i flag enables case-insensitive matching.

Syntax

db.collection.find({"fieldName": /pattern/flags});

Sample Data

Let us create a collection with documents −

db.demo727.insertMany([
   {UserId: "John@email.com"},
   {UserId: "John@yahoo.com"}, 
   {UserId: "Chris@EMAIL.com"}
]);

{
   "acknowledged" : true,
   "insertedIds" : [
      ObjectId("5eab375f43417811278f5898"),
      ObjectId("5eab376043417811278f5899"),
      ObjectId("5eab376143417811278f589a")
   ]
}

Display all documents from the collection −

db.demo727.find();

{ "_id" : ObjectId("5eab375f43417811278f5898"), "UserId" : "John@email.com" }
{ "_id" : ObjectId("5eab376043417811278f5899"), "UserId" : "John@yahoo.com" }
{ "_id" : ObjectId("5eab376143417811278f589a"), "UserId" : "Chris@EMAIL.com" }

Example: Search for "@email" Pattern

Following is the query to search for "@email" like string −

db.demo727.find({"UserId": /@email/i});

{ "_id" : ObjectId("5eab375f43417811278f5898"), "UserId" : "John@email.com" }
{ "_id" : ObjectId("5eab376143417811278f589a"), "UserId" : "Chris@EMAIL.com" }

Key Points

• The /@email/i pattern matches any string containing "@email" (case-insensitive)
• The i flag makes the search case-insensitive, matching both "email" and "EMAIL"
• Regular expressions in MongoDB use the format /pattern/flags

Conclusion

Use MongoDB regular expressions with the i flag to perform case-insensitive string pattern matching. This approach effectively searches for partial string matches within field values.