Difference between Functions And Stored procedures

Functions vs. Stored Procedures: SQL Superpowers Unveiled! 💡📦

Compare having two tools in a superhero utility belt. Each possesses unique abilities. It is the same with databases and SQL. Two similar yet different heroes exist: Functions and Stored Procedures. Let’s explore their differences and discover when to utilize their unique capabilities.

SQL Functions: The Data Transformers 🔄🎩

SQL Functions act as magical wands. They alter data and offer solutions. They accept input, enact a specific action, and return a single result.

Example: Picture a calculator app on your smartphone. When you key in numbers and press the "+" button, it performs addition and gives you the result. The addition function in this calculator app behaves like an SQL function.

-- Using SQL Function to add two numbers
CREATE FUNCTION AddNumbers (@a INT, @b INT)
RETURNS INT
AS
BEGIN
RETURN @a + @b;
END;


Now we can apply this function. To add numbers, we do this:

SELECT dbo.AddNumbers(5, 3);
-- This function call will return 8


Stored Procedures: Task Managers 📂📋

Stored Procedures serve as personal task managers. These are sets of instructions that can perform multiple tasks, such as updating data, sending emails, or executing multiple actions in sequence.

Example: Consider yourself a chef in a restaurant. A customer orders a pizza. You make the dough, add toppings, bake, and serve. Together, these steps are like an SQL Stored Procedure.

-- SQL Stored Procedure. It makes and serves pizza
CREATE PROCEDURE MakeAndServePizza
AS
BEGIN
EXEC MakePizzaDough;
EXEC AddToppings;
EXEC BakePizza;
EXEC ServePizza;
END;


Now, someone orders a pizza. You call the stored procedure:

EXEC MakeAndServePizza;


Steps? Handled for you!

Real-Life Analogy: Your Superhero Team! 🦸‍♂️🦸‍♀️

Consider SQL Functions as individual superpowers in a superhero team. Each one excels at a specific task. Now consider Stored Procedures—they are teamwork in action. Each hero does their unique part to achieve a bigger goal.

If you need a single answer or data transformation, go for SQL Functions. If you have a series of tasks to manage, call on SQL Stored Procedures and trust them to handle the mission! 🚀💥📊

Main Differences Between Functions and Stored Procedures:

Functions	Stored Procedures
A function has a return type and returns a value.	A procedure has no return type but can return values using OUT parameters.
A function can't be used with Data Manipulation queries; only SELECT queries are allowed.	With procedures, you can use DML queries like INSERT, UPDATE, SELECT, etc.
A function does not allow output parameters.	A procedure allows both input and output parameters.
Transaction management is not possible inside a function.	Transaction management is feasible within a procedure.
Calling stored procedures from functions is not allowed.	A function can be called from a stored procedure.
A function is called using a SELECT statement.	A procedure cannot be called using a SELECT statement.
Functions do not support TRY-CATCH blocks for error handling.	Procedures support TRY-CATCH blocks for exception handling.
Functions can be used in JOIN clauses as a result set.	Procedures cannot be used in JOIN clauses for queries.
In functions, only table variables are allowed, not temporary tables.	Procedures allow the use of both table variables and temporary tables.