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Database Articles
Page 20 of 547
MongoDB query to find multiple matchings inside array of objects?
To find multiple matching conditions inside an array of objects in MongoDB, use $and operator combined with $elemMatch and $regex. The $and performs a logical AND operation on multiple expressions, while $elemMatch matches documents containing an array field with at least one element matching all criteria. Syntax db.collection.find({ "$and": [ { "arrayField": { "$elemMatch": { "field1": { $regex: /pattern/i } } } }, { "arrayField": { "$elemMatch": { "field2": { $regex: /pattern/i } } } } ...
Read MoreHow to search date between two dates in MongoDB?
To search date between two dates in MongoDB, use $gte and $lt operators. The $gte operator matches dates greater than or equal to the start date, while $lt matches dates less than the end date. Syntax db.collection.find({ dateField: { $gte: new ISODate("start-date"), $lt: new ISODate("end-date") } }); Sample Data Let us create a collection with documents ? db.demo524.insertMany([ {"EndDate": new ISODate("2020-01-19")}, ...
Read MoreWhy does my MongoDB group query return always 0 in float conversion? How to fix it?
When MongoDB group queries return 0 during float conversion, it's typically because string values aren't being properly converted to numbers. Use parseFloat() or MongoDB's $toDouble operator to convert string numbers to actual numeric types. Syntax // Using parseFloat() in forEach db.collection.find({}).forEach(function(doc) { doc.field = parseFloat(doc.field); db.collection.save(doc); }); // Using $toDouble in aggregation db.collection.aggregate([ { $addFields: { "field": { $toDouble: "$field" } } } ]); Sample Data db.demo523.insertOne({ "details": { ...
Read MoreGet distinct pair of objects with all subdocuments in MongoDB?
To get a distinct pair of objects with all subdocuments in MongoDB, use the $group aggregation operator to group documents by a specific field and aggregate their values. This technique helps combine duplicate entries into unique pairs with consolidated data. Syntax db.collection.aggregate([ { $group: { _id: "$fieldToGroupBy", aggregatedField: { $operator: "$fieldToAggregate" } } ...
Read MoreHow to get latest set of data from a MongoDB collection based on the date records?
To get the latest set of data from MongoDB collection based on date records, use sort() with -1 for descending order. For a single latest document, combine with limit(1). Syntax // Get all records sorted by date (latest first) db.collection.find().sort({"dateField": -1}); // Get only the latest record db.collection.find().sort({"dateField": -1}).limit(1); Sample Data db.demo521.insertMany([ {"PurchaseDate": new ISODate("2019-01-10"), "ProductName": "Product-1"}, {"PurchaseDate": new ISODate("2020-04-05"), "ProductName": "Product-10"}, {"PurchaseDate": new ISODate("2010-05-08"), "ProductName": "Product-4"}, {"PurchaseDate": new ISODate("2020-02-21"), "ProductName": "Product-3"} ]); ...
Read MoreText search in MongoDB with Regular Expression
For text search in MongoDB with Regular Expression, use $regex operator to match patterns within string fields. This allows you to search for documents containing specific text patterns or substrings. Syntax db.collection.find({ "fieldName": { $regex: /pattern/ } }); // Alternative syntax db.collection.find({ "fieldName": { $regex: "pattern", $options: "i" } }); Sample Data db.demo519.insertMany([ {"Value": "50, 60, 70"}, {"Value": "80, 90, 50"}, {"Value": "10, 30, 40"} ]); { ...
Read MoreHow can I change the field name in MongoDB?
To change the field name in MongoDB, use the $project operator in an aggregation pipeline. This creates a projection with the new field name while mapping the value from the original field. Syntax db.collection.aggregate([ { $project: { "newFieldName": "$originalFieldName" } } ]); Create Sample Data Let us create a collection with documents − db.demo517.insertMany([ { "Name": "Chris Brown" }, { "Name": "David Miller" }, { "Name": "John Doe" } ]); { ...
Read MoreUpdate the last row with search criteria in MongoDB?
To update the last row that matches specific search criteria in MongoDB, use the findAndModify() method with a sort parameter to identify the most recent document. Syntax db.collection.findAndModify({ query: { field: "value" }, sort: { _id: -1 }, update: { $set: { field: "newValue" } }, new: true }); Sample Data db.demo516.insertMany([ { "Name": "John", "Age": 22, "Score": 56 }, { "Name": "John", "Age": 23, "Score": 67 }, ...
Read MoreMongoDB: Find name similar to Regular Expression input?
To find names similar to a regular expression input in MongoDB, use the $regex operator with the $options parameter for case-insensitive matching. Syntax db.collection.find({ "fieldName": { $regex: "pattern", $options: "i" } }); Sample Data db.demo514.insertMany([ {"Information": {"FullName": "John Doe"}}, {"Information": {"FullName": "John Smith"}}, {"Information": {"FullName": "john doe"}}, {"Information": {"FullName": "Chris Brown"}} ]); ...
Read MoreSum the score of duplicate column values in MongoDB documents?
To sum values of duplicate column entries in MongoDB, use the $group stage with $sum aggregation operator. This groups documents by a field and calculates the total of specified numeric fields. Syntax db.collection.aggregate([ { $group: { _id: "$groupingField", field1Sum: { $sum: "$field1" }, field2Sum: { $sum: "$field2" } ...
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