What is a variable in SQL Server Transact-SQL?

A variable in Transact-SQL is a symbolic name representing a memory storage that holds a piece of data.

A variable has the following the components:

1. Variable name - A symbolic name to represent the variable. Variable names in Transact-SQL must starts with the @ character. For example, @count and @price are variable names.

2. Variable data type - A predefined format on how the data is stored in the variable. For example, INTEGER and MONEY are variable types.

3. Variable value - The value represented by the data in variable storage. For example, 3 and 9.99 could be variable values stored in @count and @price variables.

4. Variable scope - The period of execution in which the variable is declared, assigned with a value and required to hold the value.

Here is an example using variables in Transact-SQL in a statement batch:

DECLARE @price MONEY;
SET @price = 9.99;
PRINT @price;

In the above example:

• The variable name is @price.
• The variable type is MONEY.
• The variable value is 9.99.
• The variable scope is the statement batch. After the execution of the statement batch, @price becomes out of scope and invalid.

⇒Variables and Data Types in SQL Server Transact-SQL

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