Database Articles - Page 240 of 618

MySQL will implicitly convert the column into a number. Following is the syntax −select * from yourTableName  order by yourColumnName*1;Let us first create a −mysql> create table DemoTable1441    -> (    -> Id varchar(30)    -> ); Query OK, 0 rows affected (0.53 sec)Insert some records in the table using insert −mysql> insert into DemoTable1441 values('301'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable1441 values('23'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable1441 values('345'); Query OK, 1 row affected (0.42 sec) mysql> insert into DemoTable1441 values('10'); Query OK, 1 row affected (0.23 sec) ... Read More

Use DEFAULT keyword in MySQL to set default value to NULL. Let us first create a −mysql> create table DemoTable1440    -> (    -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> StudentName varchar(20) DEFAULT NULL,    -> StudentAge int DEFAULT NULL    -> ); Query OK, 0 rows affected (0.55 sec)Insert some records in the table using insert command. For values left blank, the default gets inserted −mysql> insert into DemoTable1440(StudentName, StudentAge) values('Chris', 21); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable1440 values(); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable1440(StudentName) ... Read More

For specific value, use FIND_IN_SET(). Let us first create a −mysql> create table DemoTable1439    -> (    -> CountryId int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> CountryCode varchar(20)    -> ); Query OK, 0 rows affected (0.49 sec)Insert some records in the table using insert −mysql> insert into DemoTable1439(CountryCode) values('1022_US, 7894_UK'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable1439(CountryCode) values('6567_AUS, 7894_UK'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1439(CountryCode) values('6567_AUS'); Query OK, 1 row affected (0.09 sec)Display all records from the table using select −mysql> select * from DemoTable1439;This will produce the ... Read More

For this, you can use JSON data type from MySQL. Let us first create a −mysql> create table DemoTable1438    -> (    -> EmployeeDetails json    -> ); Query OK, 0 rows affected (5.97 sec)Insert some records in the table using insert −mysql> insert into DemoTable1438 values('[{"EmployeeId":"EMP-101","EmployeeName":"Chris"},{"EmployeeId":"EMP-102","EmployeeName":"David"},{"EmployeeId":"EMP-103","EmployeeName":"Sam"}]'); Query OK, 1 row affected (0.22 sec)Display all records from the table using select −mysql> select * from DemoTable1438;This will produce the following output −+------------------------------------------------------------------------------------------------------------------------------------------------------------+ | EmployeeDetails                                                                                                                                            | +------------------------------------------------------------------------------------------------------------------------------------------------------------+ | [{"EmployeeId": "EMP-101", "EmployeeName": "Chris"}, {"EmployeeId": "EMP-102", "EmployeeName": "David"}, {"EmployeeId": "EMP-103", "EmployeeName": "Sam"}] | +------------------------------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec)

For index, you can use KEY(). Let us first create a −mysql> create table DemoTable1437    -> (    -> StudentId int,    -> StudentName varchar(20),    -> StudentMarks int,    -> StudentAge int    -> ,    -> KEY(StudentId, StudentMarks, StudentAge)    -> ); Query OK, 0 rows affected (0.97 sec)Following is the query to check the description of −mysql> desc DemoTable1437;This will produce the following output −+--------------+-------------+------+-----+---------+-------+ | Field        | Type        | Null | Key | Default | Extra | +--------------+-------------+------+-----+---------+-------+ | StudentId    | int(11)     | YES  | MUL ... Read More

Let us first create a −mysql> create table DemoTable1436    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> Name varchar(20)    -> ); Query OK, 0 rows affected (1.06 sec)Insert some records in the table using insert −mysql> insert into DemoTable1436(Name) values('Chris'); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable1436(Name) values('David'); Query OK, 1 row affected (0.40 sec) mysql> insert into DemoTable1436(Name) values('Bob'); Query OK, 1 row affected (0.35 sec) mysql> insert into DemoTable1436(Name) values('David'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable1436(Name) values('David'); Query OK, 1 row affected ... Read More

To display dates like “01 August 2019”, use ORDER BY STR_TO_DATE(). Let us first create a −mysql> create table DemoTable1435    -> (    -> DueDate varchar(60)    -> ); Query OK, 0 rows affected (1.08 sec)Insert some records in the table using insert −mysql> insert into DemoTable1435 values('01 August 2019'); Query OK, 1 row affected (0.34 sec) mysql> insert into DemoTable1435 values('01 Feb 2018'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable1435 values('31 Jan 2017'); Query OK, 1 row affected (0.08 sec) mysql> insert into DemoTable1435 values('01 March 2019'); Query OK, 1 row affected (0.11 sec)Display ... Read More

For subtracting dates, use MySQL DATE_SUB(). Let us first create a −mysql> create table DemoTable1434    -> (    -> ArrivalDatetime datetime    -> ); Query OK, 0 rows affected (3.14 sec)Insert some records in the table using insert −mysql> insert into DemoTable1434 values('2019-09-30 21:10:00'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable1434 values('2018-09-30 22:20:40'); Query OK, 1 row affected (0.33 sec) mysql> insert into DemoTable1434 values('2017-09-30 23:10:00'); Query OK, 1 row affected (0.19 sec)Display all records from the table using select −mysql> select * from DemoTable1434;This will produce the following output −+---------------------+ | ArrivalDatetime     ... Read More

For this, use CONCAT_WS() in MySQL. Let us first create a −mysql> create table DemoTable1433    -> (    -> ClientId int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> ClientFirstName varchar(20),    -> ClientLastName varchar(20)    -> ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert −mysql> insert into DemoTable1433(ClientFirstName, ClientLastName) values('David', 'Miller'); Query OK, 1 row affected (0.14 sec)Display all records from the table using select −mysql> select * from DemoTable1433;This will produce the following output −+----------+-----------------+----------------+ | ClientId | ClientFirstName | ClientLastName | +----------+-----------------+----------------+ |        1 | David   ... Read More

Let us first create a −mysql> create table DemoTable1431    -> (    -> EmployeeId int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> EmployeeName varchar(20),    -> EmployeeCountryName varchar(20)    -> ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert −mysql> insert into DemoTable1431(EmployeeName, EmployeeCountryName) values('Adam Smith', 'AUS'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1431(EmployeeName, EmployeeCountryName) values('Chris Brown', 'US'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable1431(EmployeeName, EmployeeCountryName) values('John Doe', 'UK'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable1431(EmployeeName, EmployeeCountryName) values('Chris Brown', 'AUS'); Query ... Read More