To get a list of MySQL databases, following is the syntax -show databases;To get the server version, you can use the below syntax -select version();Let us implement the above syntax to get a list of MySQL databases and version -mysql> show databases;This will produce the following output displaying all the databases -+---------------------------+ | Database                  | +---------------------------+ | bothinnodbandmyisam       | | business                  | | commandline               | | customer-tracker          | | customer_tracker_database ... Read More

When you have identical dates in a table with different time values for each, you can group them easily with GROUP BY DATE.Let us first create a table -mysql> create table DemoTable692 (DueDatetime datetime); Query OK, 0 rows affected (0.97 sec)Insert some records in the table using insert command:mysql> insert into DemoTable692 values('2019-07-21 10:20:00'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable692 values('2019-06-11 11:00:10'); Query OK, 1 row affected (0.24 sec) mysql> insert into DemoTable692 values('2019-07-21 11:00:10'); Query OK, 1 row affected (1.97 sec) mysql> insert into DemoTable692 values('2019-07-21 12:10:10'); Query OK, 1 row affected (0.18 sec)Display ... Read More

For descending order result, use DESC. However, LIMIT is used to get fixed number of records −select *from yourTableName order by yourColumnName DESC LIMIT yourLimitNumber;Let us first create a table −mysql> create table DemoTable (Id int, Name varchar(100)); Query OK, 0 rows affected (0.73 sec)ExampleInsert some records in the table using insert command −mysql> insert into DemoTable values(100, 'John'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(101, 'Chris'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(102, 'Robert'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values(103, 'Bob'); Query OK, ... Read More

Let us first create a table −mysql> create table DemoTable (DueDate date); Query OK, 0 rows affected (0.92 sec)ExampleInsert some records in the table using insert command −mysql> insert into DemoTable values('2019-01-12'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('2019-04-01'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values('2019-07-19'); Query OK, 1 row affected (0.15 sec)Display all records from the table using select statement −mysql> select *from DemoTable;Output+------------+ | DueDate    | +------------+ | 2019-01-12 | | 2019-04-01 | | 2019-07-19 | +------------+ 3 rows in set (0.00 sec)Following is the query to ... Read More

For this, you can use SUBSTRING_INDEX(). Let us first create a table −mysql> create table DemoTable (Number varchar(100)); Query OK, 0 rows affected (0.60 sec)ExampleInsert some records in the table using insert command −mysql> insert into DemoTable values('235678'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values('1634990'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values('678590'); Query OK, 1 row affected (0.46 sec) mysql> insert into DemoTable values('908765432'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('222343388773'); Query OK, 1 row affected (0.35 sec) mysql> insert into DemoTable values('09028215'); Query OK, ... Read More

For this, use GROUP BY and HAVING. Let us first create a table −mysql> create table DemoTable    (    StudentName varchar(100),    DueDate date    ); Query OK, 0 rows affected (0.72 sec)ExampleInsert some records in the table using insert command −mysql> insert into DemoTable values('John', '2019-01-11'); Query OK, 1 row affected (0.26 sec) mysql> insert into DemoTable values('Chris', '2019-02-11'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values('Chris', '2019-03-11'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('John', '2019-04-11'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('Bob', '2019-05-11'); ... Read More

Yes, an alternative is CONCAT_WS(). Let us first create a table −mysql> create table DemoTable    (    StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY,    StudentName varchar(100)    ); Query OK, 0 rows affected (0.74 sec)ExampleInsert some records in the table using insert command −mysql> insert into DemoTable(StudentName) values('Chris'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable(StudentName) values('Robert'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(StudentName) values('Bob'); Query OK, 1 row affected (0.12 sec)Display all records from the table using select statement −mysql> select *from DemoTable;Output+-----------+-------------+ | StudentId | StudentName | +-----------+-------------+ | ... Read More

For this, use REPLACE() function and replace empty space with the character. Let us first create a table −mysql> create table DemoTable (Subject text); Query OK, 0 rows affected (0.86 sec)ExampleInsert some records in the table using insert command −mysql> insert into DemoTable values('Introduction to MySQL'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('Java in depth'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable values('Data Structure and Algorithm'); Query OK, 1 row affected (0.16 sec)Display all records from the table using select statement −mysql> select *from DemoTable;Output+------------------------------+ | Subject | +------------------------------+ | Introduction ... Read More

Use index to select top n rows efficiently. Let us first create a table −mysql> create table DemoTable (StudentName varchar(100), StudentScore int ); Query OK, 0 rows affected (0.66 sec)ExampleInsert some records in the table using insert command −mysql> insert into DemoTable values('John', 34); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('Carol', 55); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('Bob', 58); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values('Sam', 38); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Mike', 48); Query OK, 1 row ... Read More

For this, you can use CHAR_LENGTH(). Use RAND() for random records. Let us first create a table −mysql> create table DemoTable (Subject text); Query OK, 0 rows affected (0.61 sec)ExampleInsert some records in the table using insert command −mysql> insert into DemoTable values('C'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values('MySQL'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Java'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('MongoDB'); Query OK, 1 row affected (0.59 sec) mysql> insert into DemoTable values('RubyOnRails'); Query OK, 1 row affected (0.25 sec) mysql> insert ... Read More