Found 6702 Articles for Database

Update the content of a specific cell in MySQL

AmitDiwan
Updated on 06-Apr-2020 13:42:37

462 Views

Let us first create a table −mysql> create table DemoTable2029    -> (    -> Id int,    -> FirstName varchar(20),    -> LastName varchar(20)    -> ); Query OK, 0 rows affected (0.98 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2029 values(1, 'Chris', 'Brown') -> ; Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable2029 values(2, 'David', 'Miller'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable2029 values(3, 'John', 'Smith'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable2029 values(4, 'John', 'Brown'); Query OK, 1 ... Read More

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

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

356 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 procedure insert_name(in fname varchar(20), in lname varchar(20))    -> begin    -> insert into DemoTable2028 values(fname, lname);    -> end    -> // Query OK, 0 rows affected (0.17 sec) mysql> delimiter ;Call the stored procedure using CALL command −mysql> call insert_name('Chris', 'Brown'); Query OK, 1 row affected (0.17 sec)Display ... Read More

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

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

435 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" : 0,    "nMatched" : 0,    "nModified" : 0,    "nRemoved" : 0,    "upserted" : [ ] })Display all documents from a collection with the help of find() method −> db.demo446.find();This will produce the following output −{ "_id" : ObjectId("5e790766bbc41e36cc3caec3"), "ProductName" : "Product1", "ProductPrice" : 60 } { ... Read More

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

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

338 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 into DemoTable2027 values(20); Query OK, 1 row affected (0.28 sec) mysql> insert into DemoTable2027 values(31); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable2027 values(11); Query OK, 1 row affected (0.12 sec)Display all records from the table using select statement −mysql> select *from DemoTable2027;This will produce ... Read More

Cannot push into an array from MongoDB?

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

120 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 output −{    "_id" : ObjectId("5e78f099bbc41e36cc3caec2"),    "ListOfFriends" : [       "Robert",       "Mike",       "Sam",       "Carol",       "David",       "Mike"    ] }Following is the query to push into an array −> db.demo445.update( ...    { ... Read More

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

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

126 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 table using insert command. We are first converting the VARCHAR date and then adding minutes −mysql> insert into DemoTable2026 values(date_add(str_to_date('2017-12-01 11:34:45', '%Y-%m-%d %H:%i:%s'), INTERVAL 10 MINUTE)); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable2026 values(date_add(str_to_date('2015-01-31 10:00:00', '%Y-%m-%d %H:%i:%s'), INTERVAL 5 MINUTE)); Query OK, 1 row affected ... Read More

How to improve MongoDB queries with multikey index in array?

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

126 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" ...       }] ...    } ... ); {    "acknowledged" : true,    "insertedId" : ObjectId("5e78ea87bbc41e36cc3caebf") } > db.demo444.insertOne( ...    { ...       "Information": [{ ...          id:2, ...          Name:"David" ...       }] ...    } ... ); {    "acknowledged" : true,   ... Read More

Find and replace a part of URL records in MySQL?

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

744 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 sec) mysql> insert into DemoTable2025 values('http=//www.google.com'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable2025 values('http=//www.gmail.com'); Query OK, 1 row affected (0.26 sec)Display all records from the table using select statement −mysql> select *from DemoTable2025;This will produce the following output −+-------------------------+ | URL ... Read More

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

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

172 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") } > db.demo443.insertOne({"Name":"David"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e78d288bbc41e36cc3caebb") }Display all documents from a collection with the help of find() method −> db.demo443.find();This will produce the following output −{ "_id" : ObjectId("5e78d281bbc41e36cc3caeb9"), "Name" : "Chris" } { "_id" : ObjectId("5e78d285bbc41e36cc3caeba"), "Name" : "Bob" } { "_id" : ... Read More

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

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

675 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 OK, 1 row affected (0.13 sec) mysql> insert into DemoTable2024 values('MySQL', 'David'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable2024 values('MongoDB', 'Bob'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable2024 values('Java', 'Sam'); Query OK, 1 row affected (0.18 sec) mysql> ... Read More

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