Using Parameters

What is a Parameter?

A parameter is a placeholder for a variable that contains a value of some type passed to a database server along with the SQL text at the query execution time. Also, a parameter can hold values returned by a server after query or stored procedure execution.

You can benefit from using parameters in the following situations:

  • When you execute a query multiple times with different input values
  • When you debug a query from your application code

Adding Parameters to a Query Text

Parameters are declared using the @ prefix followed by a parameter name. A prefix is included to a parameter name.

For example:

SELECT
  Employee.*
FROM
  HumanResources.Employee
WHERE
  Employee.Title = @Job AND
  Employee.VacationHours <= @Level

@Job and @Level are parameters in this query.

Modifying Parameter Values and Types

When you run a query that contains parameters with empty values, you will automatically be prompted to initialize them.

To set parameter values and types, select Edit Parameters on the SQL toolbar, or press F8. In the Edit Parameters dialog box that appears, set parameter type, value, and other properties.

Note

When you execute a query with preset parameter values, you will not be automatically prompted to edit them. To edit parameters, press F8 or select Edit Parameters on the SQL toolbar.