Let us first create a table −mysql> create table DemoTable (    Number int ); Query OK, 0 rows affected (0.80 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(189); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(178); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(876); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values(784); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values(988); Query OK, 1 row affected (0.23 sec)Display all records from the table using select statement −mysql> select ... Read More

Let us first create a table −mysql> create table DemoTable (    Id int,    Name varchar(50) ); Query OK, 0 rows affected (0.47 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(1001, 'Robert'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(1002, 'Sam'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(1003, 'Tom'); Query OK, 1 row affected (0.10 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+------+--------+ | Id | Name | ... Read More

For this, you can use a CASE statement. Let us first create a table −mysql> create table DemoTable (    ProductName varchar(100),    ProductRating ENUM('1', '2', '3') ); Query OK, 0 rows affected (0.50 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Product-1', 3); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('Product-2', 1); Query OK, 1 row affected (0.08 sec) mysql> insert into DemoTable values('Product-3', 2); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('Product-1', 2); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values('Product-3', ... Read More

To insert multiple parameter values into a single column, use the CONCAT_WS() or CONCAT(). Let us first create a table −mysql> create table DemoTable (    Name varchar(100),    Age int,    CountryName varchar(100),    PersonInformation text ); Query OK, 0 rows affected (0.67 sec)Following is the query to insert multiple parameter values into a single column. We will do this using the same INSERT command, which is used to insert records in a MySQL table −mysql> insert into DemoTable values('John', 21, 'US', concat_ws('-', Name, Age, CountryName)); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('Chris', 22, ... Read More

For user-defined variables, we use @ in MySQL. Following is the syntax. Here, @anyVariableName is our user-defined variable −select yourColumnName into @anyVariableName from yourTableName where yourCondition;Let us first create a table −mysql> create table DemoTable (    Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    Name varchar(100) ); Query OK, 0 rows affected (0.73 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(Name) values('Chris'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable(Name) values('Robert'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable(Name) values('David'); Query OK, 1 row affected (0.10 sec)Display all ... Read More

To get the length of all columns i.e. the count of all the characters for column values, use char_length(). Let us first create a table. Here, we have two columns, therefore we will calculate for each row consisting of both the values FirstName and LastName −mysql> create table DemoTable (    FirstName varchar(100),    LastName varchar(100) ); Query OK, 0 rows affected (1.07 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Chris', 'Brown'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values('David', 'Miller'); Query OK, 1 row affected (0.11 sec) mysql> insert ... Read More

Following is the syntax −delete from yourTableName where yourColumnName < (yourAnotherDateValue - INTERVAL 30 DAY);Let us first create a table −mysql> create table DemoTable (    DueDate date ); Query OK, 0 rows affected (0.68 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2019-08-25'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values('2019-07-01'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values('2019-06-20'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values('2019-09-02'); Query OK, 1 row affected (0.14 sec)Display all records from the table using select statement ... Read More

For this, use CONCAT() method in MySQL. Let us first create a table −mysql> create table DemoTable (    FirstName varchar(50),    LastName varchar(50) ); Query OK, 0 rows affected (0.63 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Chris', 'Brown'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable values('David', 'Miller'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values('John', 'Doe'); Query OK, 1 row affected (0.08 sec) mysql> insert into DemoTable values('Adam', 'Smith'); Query OK, 1 row affected (0.25 sec)Display all records from the table using select statement ... Read More

To alter column type of multiple columns in a single MySQL query, the syntax is as follows −alter table yourTableName modify column yourColumnName 1 yourDataType1, modify column yourColumnName 2 yourDataType2, . . N;Let us first create a table −mysql> create table DemoTable (    Id varchar(100),    FirstName text,    LastName text ); Query OK, 0 rows affected (0.52 sec)Let us check the description of table −mysql> desc DemoTable;This will produce the following output −+-----------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | ... Read More

For this, you can use the CASE statement along with SUM(). Here, we will be finding the count of Male and Female records from a column with employee gender values. Let us first create a table −mysql> create table DemoTable (    EmployeeGender ENUM('Male', 'Female') ); Query OK, 0 rows affected (0.52 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Male'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('Female'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('Male'); Query OK, 1 row affected (0.10 sec) mysql> insert into ... Read More