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To swap two values in a column, use CASE WHEN statement. Let us first create a table −mysql> create table DemoTable1382 -> ( -> StudentName varchar(20) -> ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1382 values('John'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable1382 values('Chris'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable1382 values('Adam'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable1382 values('Bob'); Query OK, 1 row affected (0.17 sec)Display all records from the table using ... Read More
For maximum value, use MAX() along with CAST() for conversion. Since we want maximum value from string-numbers beginning with specific characters, use RLIKE. Let us first create a table −mysql> create table DemoTable1381 -> ( -> DepartmentId varchar(40) -> ); Query OK, 0 rows affected (0.48 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1381 values('IT794'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable1381 values('AT1034'); Query OK, 1 row affected (0.52 sec) mysql> insert into DemoTable1381 values('IT967'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1381 values('IT874'); Query ... Read More
Let us first create a table −mysql> create table DemoTable1 -> ( -> StudentId int, -> StudentName varchar(20) -> ); Query OK, 0 rows affected (1.24 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1 values(210, 'Adam'); Query OK, 1 row affected (0.11 sec)Display all records from the table using select statement −mysql> select * from DemoTable1;This will produce the following output −+-----------+-------------+ | StudentId | StudentName | +-----------+-------------+ | 210 | Adam | +-----------+-------------+ 1 row in set (0.00 sec)Here is the query to create ... Read More
To view cascades, use SHOW CREATE TABLE in MySQL. Let us first create a table −mysql> create table DemoTable1378 -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> EmployeeId varchar(20), -> EmployeeFirstName varchar(20), -> EmployeeLastName varchar(20), -> EmployeeCountryName varchar(40), -> EmployeeAge int, -> EmployeeSalary int, -> UNIQUE(EmployeeFirstName, EmployeeSalary), -> INDEX First_Last_NameIndex(EmployeeFirstName, EmployeeLastName) -> ); Query OK, 0 rows affected (0.93 sec)Let us now view cascades in MySQL −mysql> show create table DemoTable1378;This will produce the following output −+---------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Table | Create Table ... Read More
For this, use INTERVAL in MySQL. Let us first create a table −mysql> create table DemoTable1376 -> ( -> AdmissionDate date -> ); Query OK, 0 rows affected (0.68 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1376 values('2018-01-21'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1376 values('2017-12-01'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable1376 values('2018-11-02'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1376 values('2019-03-14'); Query OK, 1 row affected (0.17 sec)Display all records from the table using select statement−mysql> select * from ... Read More
The EXPLAIN keyword tells how MySQL executes the query. Let us first create a table −mysql> create table DemoTable1375 -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> FirstName varchar(20), -> INDEX FIRST_INDEX(FirstName) -> ); Query OK, 0 rows affected (0.73 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1375(FirstName) values('Chris'); Query OK, 1 row affected (0.25 sec) mysql> insert into DemoTable1375(FirstName) values('Bob'); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable1375(FirstName) values('Sam'); Query OK, 1 row affected (1.06 sec) mysql> insert into DemoTable1375(FirstName) values('David'); Query OK, ... Read More
Use CASE WHEN for this in MySQL and set CASE condition inside the COUNT() method to count. Let us first create a table −mysql> create table DemoTable1374 -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Name varchar(20), -> Score int -> ); Query OK, 0 rows affected (0.61 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1374(Name, Score) values('Chris', 45); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1374(Name, Score) values('David', 78); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable1374(Name, Score) values('Bob', 45); ... Read More
To display records like JSON format, use MySQL concat(). Let us first create a table −mysql> create table DemoTable1373 -> ( -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentDetails text -> ); Query OK, 0 rows affected (0.86 sec)Insert some records in the table using insert command. Here, we haven’t inserted anything −mysql> insert into DemoTable1373 values(); Query OK, 1 row affected (0.27 sec) mysql> insert into DemoTable1373 values(); Query OK, 1 row affected (0.08 sec) mysql> insert into DemoTable1373 values(); Query OK, 1 row affected (0.18 sec)Display all records from the table using ... Read More
For this, just update the table and subtract. Let us first create a table −mysql> create table DemoTable1372 -> ( -> Value int -> ); Query OK, 0 rows affected (0.77 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1372 values(500); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1372 values(100); Query OK, 1 row affected (0.24 sec) mysql> insert into DemoTable1372 values(900); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable1372 values(1000); Query OK, 1 row affected (0.32 sec)Display all records from the table using select statement −mysql> ... Read More
For this, use GROUP_CONCAT(). Do not use GROUP BY clause, since GROUP_CONTACT() is a better and quick solution.Let us first create a table −mysql> create table DemoTable1371 -> ( -> Id int, -> CountryName varchar(40) -> ); Query OK, 0 rows affected (0.89 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1371 values(100, 'US'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable1371 values(100, 'UK'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable1371 values(101, 'AUS'); Query OK, 1 row affected (0.27 sec) mysql> insert into DemoTable1371 values(101, ... Read More
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