Do you have to declare variables in SQL?

Why do you DECLARE a variable in SQL?

Variables in SQL procedures are defined by using the DECLARE statement. Values can be assigned to variables using the SET statement or the SELECT INTO statement or as a default value when the variable is declared. Literals, expressions, the result of a query, and special register values can be assigned to variables.

How do you set a variable in SQL query?

When a variable is first declared, its value is set to NULL. To assign a value to a variable, use the SET statement. This is the preferred method of assigning a value to a variable. A variable can also have a value assigned by being referenced in the select list of a SELECT statement.

Where do we DECLARE SQL variable?

Variables are declared in the body of a batch or procedure with the DECLARE statement and are assigned values by using either a SET or SELECT statement.

What are the rules for naming variables in SQL?

PL/SQL variables naming rulesThe variable name must be less than 31 characters. Try to make it as meaningful as possible within 31 characters.The variable name must begin with an ASCII letter. ... Followed by the first character are any number, underscore ( _ ), and dollar sign ( $ ) characters.PL/SQL Variables