MariaDB: Declaring Variables

This MariaDB tutorial explains how to declare variables in MariaDB with syntax and examples.

What is a variable in MariaDB?

In MariaDB, a variable allows a programmer to store data temporarily during the execution of code.

Syntax

The syntax to declare a variable in MariaDB is:

DECLARE variable_name datatype [ DEFAULT initial_value ]

Parameters or Arguments

variable_name

The name to assign to the variable.

datatype

The datatype to assign to the variable.

DEFAULT initial_value

Optional. It is the value initially assigned to the variable when it is declared. If an initial_value is not specified, the variable is assigned an initial value of NULL.

Example - Declaring a variable

Below is an example of how to declare a variable in MariaDB called Website.

DECLARE Website VARCHAR(45);

This example would declare a variable called Website as a VARCHAR(45) data type.

You can then later set or change the value of the Website variable, as follows:

SET Website = 'CheckYourMath.com';

This SET statement would set the Website variable to a value of 'CheckYourMath.com'.

Example - Declaring a variable with an initial value (not a constant)

Below is an example of how to declare a variable in MariaDB and give it an initial value. This is different from a constant in that the variable's value can be changed later.

DECLARE Website VARCHAR(45) DEFAULT 'CheckYourMath.com';

This would declare a variable called Website as a VARCHAR(45) data type and assign an initial value of 'CheckYourMath.com'.

You could later change the value of the Website variable, as follows:

SET Website = 'TechOnTheNet.com';

This SET statement would change the Website variable from a value of 'CheckYourMath.com' to a value of 'TechOnTheNet.com'.