How to use SQL stored procedures

You can use SQL stored procedures to save frequently used queries and procedures as code blocks that can be easily retrieved later. They can save you time and ensure that you don’t have to type up SQL statements anew each time you use them.

What are SQL stored procedures?

In your work with SQL, there are sure to be statements that you use over and over again. Entering complex statements from scratch every time you need them can cost you time and increase the possibility of errors. SQL stored procedures make it easier to work with regular, complex queries. You can use it to store and retrieve blocks of code that you use frequently. That way you can automate recurring procedures and make your data management more efficient.

One advantage of SQL stored procedures is that you can store pretty much any kind of statement containing SQL functions, SQL commands or SQL operators and execute pretty much any kind of task. You can create stored procedures for the action in question and invoke them by inserting the PROCEDURE name into regular statements like SQL UPDATE and SQL SELECT. The functions you can automate with SQL stored procedures include updates, queries, deleting data and outputting values.

What is the syntax of SQL stored procedures?

The syntax of any particular stored procedure will depend on the code block that you want to save and might be more or less complex.

Here’s the syntax for a simple stored procedure:

CREATE PROCEDURE Procedure_name (Parameter1 file_type, Parameter2 file_type, …)
AS
BEGIN
(Code block you want to save)
END;

Depending on which database management system you use, the syntax might also look as follows:

CREATE PROCEDURE Procedure_name (Parameter1 file_type, Parameter2 file_type, …)
AS
(Code block you want to save)
GO;

These are the parameters involved:

• CREATE PROCEDURE: Define the name of your procedure here. This is the name you’ll use to execute the code or insert it into another statement. Parameters include the different data needed for the code block, including their file type.
• AS: Marks the beginning of the code block that you want to save as a stored procedure.
• BEGIN + END: Mark the beginning and end of the code block you want to save.
• GO: Marks the end of the code block (has the same function as END).

You can execute a stored procedure using this code:

EXEC Procedure_name;

What are the advantages and use cases of SQL stored procedures?

With SQL stored procedures, you can store pretty much any SQL statement and retrieve it later. The advantages of stored procedures include:

• Reuse code: There are certain SQL commands and functions that you’ll use over and over again with your database. Storing simple and complex statements allows you to use them repeatedly without having to enter the code every time.
• Simplified work with databases: When it comes to complex tasks, stored procedures break up large, complex operations into several smaller procedures. Code blocks are treated like modules that can be incorporated into the statement you’re working on.
• More efficiency, better performance: Storing code blocks makes it easier to create SQL statements and improve the performance of large databases.
• More security: Assigning permissions to stored procedures ensures that sensitive data can only be retrieved or accessed with authorization.

Some practical use cases for SQL stored procedures from various industries include:

• Automating order processes and updating customer data
• Monitoring and checking suspicious financial transactions or calculating interest rates
• Automatically creating offers based on customer data, purchase behavior, order volume and region
• Calculating employee commissions based on performance
• Creating finance reports and posting transactions
• Tracking, monitoring and syncing inventory and incoming orders

Examples of SQL stored procedures

We’ll now turn to two examples of SQL stored procedures.

Retrieving all customers

Let’s say you want to retrieve all the customer data from a table called “Customers”. That would look like this:

CREATE PROCEDURE SelectAllCustomers
AS
BEGIN
SELECT * FROM Customers
END;

Selecting orders from one city

Now let’s say you want to retrieve all the orders from one city from a table called “Orders”:

CREATE PROCEDURE SelectAllOrdersChicago
AS
BEGIN
SELECT * FROM Orders WHERE City = 'Chicago'
END;

Are there alternatives to SQL stored procedures?

There are several alternatives to SQL stored procedures with a similar function. They include:

• UDF (User Defined Function): UDFs allow you to create and save your own functions using the keyword CREATE FUNCTION. That enables you to integrate complex queries into SQL statements as predefined functions, without needing to type in the entire block of code.
• VIEWS: VIEWS enables you to create empty, virtual tables for analyzing records with pre-defined parameters. Like UDFs and stored procedures, you can insert VIEWS as an element in SQL statements.