AmitDiwan has Published 10744 Articles

How to aggregate two collections where a field from one collection is greater than the other in MongoDB?

AmitDiwan

AmitDiwan

Updated on 06-Apr-2020 13:40:32

521 Views

For this, you can use $lookup. Let us create a collection with documents −> db.demo446.insert([ ...    { "ProductName": "Product1", "ProductPrice": 60 }, ...    { "ProductName": "Product2", "ProductPrice": 90 } ... ]) BulkWriteResult({    "writeErrors" : [ ],    "writeConcernErrors" : [ ],    "nInserted" : 2,    "nUpserted" ... Read More

How to correctly use delimiter in a MySQL stored procedure and insert values?

AmitDiwan

AmitDiwan

Updated on 06-Apr-2020 13:38:34

468 Views

Let us first create a table −mysql> create table DemoTable2028    -> (    -> StudentFirstName varchar(20),    -> StudentLastName varchar(20)    -> ); Query OK, 0 rows affected (0.87 sec)Here is the query to create a stored procedure and insert values (using delimiter correctly) −mysql> delimiter // mysql> create ... Read More

Cannot push into an array from MongoDB?

AmitDiwan

AmitDiwan

Updated on 06-Apr-2020 13:36:21

177 Views

To push into an array with MongoDB, use $push. Let us create a collection with documents −> db.demo445.insertOne({"ListOfFriends":["Robert", "Mike", "Sam", "Carol", "David", "Mike"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e78f099bbc41e36cc3caec2") }Display all documents from a collection with the help of find() method −> db.demo445.find().pretty();This will produce the following ... Read More

How to write a valid MySQL query and update with a custom variable?

AmitDiwan

AmitDiwan

Updated on 06-Apr-2020 13:35:56

388 Views

Let us first create a table −mysql> create table DemoTable2027    -> (    -> UserId int    -> ); Query OK, 0 rows affected (0.65 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2027 values(10); Query OK, 1 row affected (0.18 sec) mysql> insert ... Read More

Can we add minutes to VARCHAR datetime records while applying INSERT statement in MySQL?

AmitDiwan

AmitDiwan

Updated on 06-Apr-2020 13:33:31

180 Views

Yes, we can add minutes while inserting values in a table.Let us first create a table. Here, we have a column with VARCHAR records where inmysql> create table DemoTable2026    -> (    -> ArrivalTime varchar(20)    -> ); Query OK, 0 rows affected (0.40 sec)Insert some records in the ... Read More

How to improve MongoDB queries with multikey index in array?

AmitDiwan

AmitDiwan

Updated on 06-Apr-2020 13:32:46

178 Views

For this, use $elemMatch, which is used to query nested objects. Let us create a collection with documents −> db.demo444.insertOne( ...    { ...       "Information": [{ ...          id:1, ...          Name:"Chris" ...       }] ...    } ... ... Read More

Find and replace a part of URL records in MySQL?

AmitDiwan

AmitDiwan

Updated on 06-Apr-2020 13:31:49

946 Views

The simplest way to replace records is using MySQL REPLACE() −mysql> create table DemoTable2025    -> (    -> URL text    -> ); Query OK, 0 rows affected (0.88 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2025 values('http=//www.facebook.com'); Query OK, 1 row affected (0.23 ... Read More

MongoDB profiler output: What is the “command” operation?

AmitDiwan

AmitDiwan

Updated on 06-Apr-2020 13:30:22

246 Views

The following operations are treated as command operation in MongoDB −1.count 2.findAndModify 3.aggregateFollowing is the example of count in MongoDB −Let us create a collection with documents −> db.demo443.insertOne({"Name":"Chris"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e78d281bbc41e36cc3caeb9") } > db.demo443.insertOne({"Name":"Bob"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e78d285bbc41e36cc3caeba") ... Read More

Return a list from different rows into a single field with MySQL

AmitDiwan

AmitDiwan

Updated on 06-Apr-2020 13:29:37

885 Views

For this, use GROUP_CONCAT(). Let us first create a table −mysql> create table DemoTable2024    -> (    -> SubjectName varchar(20),    -> StudentName varchar(20)    -> ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2024 values('MySQL', 'Chris'); Query ... Read More

Getting distinct values from object array in MongoDB?

AmitDiwan

AmitDiwan

Updated on 06-Apr-2020 13:28:05

1K+ Views

To get distinct values from object array in MongoDB, use distinct(). Let us create a collection with documents −> db.demo442.insertOne( ...    { ... ...       "Information" : [ ...          { ...             "FirstName" : "John", ...     ... Read More

Advertisements