Let us first create a collection with documents −> db.findOneWorkingDemo.insertOne({"ClientId":1, "ClientName":"Larry", "ClientAge":26}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd7c1716d78f205348bc64d") } > db.findOneWorkingDemo.insertOne({"ClientId":2, "ClientName":"Chris", "ClientAge":28}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd7c17d6d78f205348bc64e") } > db.findOneWorkingDemo.insertOne({"ClientId":3, "ClientName":"Robert", "ClientAge":34}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd7c1896d78f205348bc64f") }Following is the query to display all documents from a collection with the help of find() method −> db.findOneWorkingDemo.find().pretty();This will produce the following output −{    "_id" : ObjectId("5cd7c1716d78f205348bc64d"),    "ClientId" : 1,    "ClientName" : "Larry",    "ClientAge" : 26 } {    "_id" : ObjectId("5cd7c17d6d78f205348bc64e"),    "ClientId" : 2, ... Read More

Here, now() represents the current date. To check whether it falls between two specific dates, you need to use the BETWEEN. Let us first create a table −mysql> create table DemoTable    (    FirstDate datetime,    SecondDate datetime    ); Query OK, 0 rows affected (0.60 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2019-04-01', '2019-05-02'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values('2019-05-28', '2019-06-04'); Query OK, 1 row affected (0.27 sec) mysql> insert into DemoTable values('2016-01-31', '2019-03-01'); Query OK, 1 row affected (0.15 sec)Display all records from the table ... Read More

Use GREATEST() to find the maximum. Let us first create a table −mysql> create table DemoTable1    (    Number int    ); Query OK, 0 rows affected (0.52 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1 values(80); Query OK, 1 row affected (0.26 sec) mysql> insert into DemoTable1 values(229); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable1 values(575); Query OK, 1 row affected (0.24 sec)Display all records from the table using select statement −mysql> select *from DemoTable1;Output+--------+ | Number | +--------+ | 80 | | 229 ... Read More

Use ORDER BY clause for this. Let us first create a table −mysql> create table DemoTable    (    Value1 int,    Value2 int    ); Query OK, 0 rows affected (0.54 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10, 40); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values(50, 5); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(51, 56); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(52, 78); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values(90, 7); Query ... Read More

For this, use the CASE statement. Let us first create a table −mysql> create table DemoTable    (    Number int    ); Query OK, 0 rows affected (0.83 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values(0); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(20); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(50); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values(0); Query OK, 1 row affected (0.09 sec) mysql> insert ... Read More

To calculate timestamp difference, use aggregate framework. Let us first create a collection with documents −> db.timestampDifferenceDemo.insertOne({    "MovieBeginningTime": new ISODate("2019-05-12 10:20:30"),    "MovieEndingTime":new ISODate("2019-05-12 12:30:20") }); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd7ba1f6d78f205348bc644") } > db.timestampDifferenceDemo.insertOne({    "MovieBeginningTime": new ISODate("2019-05-12 04:00:00"),    "MovieEndingTime":new ISODate("2019-05-12 07:10:00") }); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd7ba3b6d78f205348bc645") }Following is the query to display all documents from a collection with the help of find() method −> db.timestampDifferenceDemo.find().pretty();This will produce the following output −{    "_id" : ObjectId("5cd7ba1f6d78f205348bc644"),    "MovieBeginningTime" : ISODate("2019-05-12T10:20:30Z"),    "MovieEndingTime" : ISODate("2019-05-12T12:30:20Z") } {    "_id" : ... Read More

Yes, we can do that. Let us first create a table −mysql> create table DemoTable    (    ID int,    GameScore int    ); Query OK, 0 rows affected (0.55 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(15, 848747); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values(13, 909049); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(34, 98474646); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(31, 948474); Query OK, 1 row affected (0.27 sec)Display all records from the table using select statement ... Read More

Yes, you can use the findOne(). Following is the syntax −db.yourCollectionName.findOne();You can use toArray() as well −db.yourCollectionName.find().toArray();Let us first create a collection with documents −> db.betterFormatDemo.insertOne({"StudentName":"Adam Smith", "StudentScores":[98, 67, 89]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd7ab826d78f205348bc640") } > db.betterFormatDemo.insertOne({"StudentName":"John Doe", "StudentScores":[67, 89, 56]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd7ab936d78f205348bc641") } > db.betterFormatDemo.insertOne({"StudentName":"Sam Williams", "StudentScores":[45, 43, 33]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd7aba76d78f205348bc642") }Following is the query to display all documents from a collection with the help of find() method −> db.betterFormatDemo.find();This will produce the following output −{ "_id" : ObjectId("5cd7ab826d78f205348bc640"), "StudentName" ... Read More

The word order is a reserved order in MySQL and you have used it in the query. To get rid of the syntax error, you need to use backticks(` `) around the order.The correct syntax is as follows −select *from yourTableName ORDER BY `order` DESC;Let us first create a table −mysql> create table DemoTable    (    `order` int    ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(89); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values(67); Query OK, 1 row affected (0.13 sec) ... Read More

For this, use both GROUP BY and ORDER BY clause. Let us first create a table −mysql> create table DemoTable    (    StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY,    StudentGrade char(1)    ); Query OK, 0 rows affected (0.87 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(StudentGrade) values('A'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable(StudentGrade) values('F'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(StudentGrade) values('C'); Query OK, 1 row affected (0.28 sec) mysql> insert into DemoTable(StudentGrade) values('A'); Query OK, 1 row affected (0.23 sec) mysql> insert ... Read More