How can you create a stored procedure that accepts input and returns output parameters?

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Stored procedures are powerful tools for data analysis, as they allow you to execute complex queries and manipulate data with parameters. Parameters are values that you can pass to or receive from a stored procedure, making it more flexible and reusable. In this article, you will learn how to create a stored procedure that accepts input and returns output parameters using T-SQL, the language for Microsoft SQL Server.

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1 What are input and output parameters?

Input parameters are values that you provide to a stored procedure when you call it, and they are used as variables in the query. For example, you can use input parameters to filter, sort, or join data based on the values you specify. Output parameters are values that a stored procedure returns to the caller after it finishes executing, and they are usually used to return some results or status information. For example, you can use output parameters to return the number of rows affected, the average value of a column, or an error message.

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2 How to declare input and output parameters?

To declare input and output parameters, you need to use the CREATE PROCEDURE statement, followed by the name of the stored procedure and a list of parameters in parentheses. Each parameter has a name, a data type, and an optional default value. To indicate that a parameter is an output parameter, you need to add the OUTPUT keyword after the data type. For example, the following statement creates a stored procedure named GetSalesByYear that accepts two input parameters (year and region) and returns one output parameter (total sales):

CREATE PROCEDURE GetSalesByYear
@year INT,
@region VARCHAR(50),
@total_sales DECIMAL(18,2) OUTPUT
AS
-- query logic goes here

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3 How to pass input and output parameters?

To pass input and output parameters, you need to use the EXECUTE statement, followed by the name of the stored procedure and a list of parameters in parentheses. You can pass input parameters by name or by position, but you need to use the same order as in the declaration. To pass output parameters, you need to declare a variable with the same data type as the parameter, and use the OUTPUT keyword after the variable name. For example, the following statement executes the stored procedure named GetSalesByYear and passes two input parameters (2020 and North America) and one output parameter (total sales):

DECLARE @total_sales DECIMAL(18,2)
EXECUTE GetSalesByYear 2020, 'North America', @total_sales OUTPUT
-- display or use the output parameter value

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4 How to set input and output parameters?

To set input and output parameters, you need to write the query logic inside the stored procedure using T-SQL statements. You can use input parameters as variables in the query, and assign values to output parameters using the SET or SELECT statement. For example, the following query logic calculates the total sales for the given year and region, and assigns the result to the output parameter:

-- query logic inside the stored procedure
BEGIN
SET @total_sales = (
SELECT SUM(sales_amount) FROM sales
WHERE sales_year = @year AND sales_region = @region
)
END

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Parveen Jain

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DECLARE @EmpFirstName NVARCHAR(50), @EmpLastName NVARCHAR(50) CREATE PROCEDURE sp_GetEmployeeDetails @EmployeeID INT, @FirstName NVARCHAR(50) OUTPUT, @LastName NVARCHAR(50) OUTPUT AS BEGIN SELECT @FirstName = FirstName, @LastName = LastName FROM Employees WHERE EmployeeID = @EmployeeID END EXEC sp_GetEmployeeDetails @EmployeeID = 123, @FirstName = @EmpFirstName OUTPUT, @LastName = @EmpLastName OUTPUT SELECT @EmpFirstName AS FirstName, @EmpLastName AS LastName

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5 How to handle errors with output parameters?

To handle errors with output parameters, you can use the TRY...CATCH block inside the stored procedure, and use the RAISERROR or THROW statement to generate an error message. You can also use an output parameter to return the error code or message to the caller, and check its value after executing the stored procedure. For example, the following query logic checks if the input parameters are valid, and raises an error if not. It also uses an output parameter to return the error code:

-- query logic inside the stored procedure with error handling
BEGIN TRY
IF @year < 2000 OR @year > 2020
RAISERROR('Invalid year value', 16, 1)
IF @region NOT IN ('North America', 'Europe', 'Asia')
RAISERROR('Invalid region value', 16, 1)
-- calculate and set the output parameter value
END TRY
BEGIN CATCH
-- set the output parameter value to the error number
SET @total_sales = ERROR_NUMBER()
END CATCH

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6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?

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How can you create a stored procedure that accepts input and returns output parameters?

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1 What are input and output parameters?

2 How to declare input and output parameters?

3 How to pass input and output parameters?

4 How to set input and output parameters?

5 How to handle errors with output parameters?

6 Here’s what else to consider

Data Architecture

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How can you create a stored procedure that accepts input and returns output parameters?

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6

1 What are input and output parameters?

2 How to declare input and output parameters?

3 How to pass input and output parameters?

4 How to set input and output parameters?

5 How to handle errors with output parameters?

6 Here’s what else to consider

Data Architecture

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