SQL Stored Procedures

SQL Tutorial

Here is a clear, complete, and practical guide to SQL Stored Procedures, with examples for MySQL, PostgreSQL, and SQL Server.

What Are SQL Stored Procedures?

A stored procedure is a precompiled block of SQL code stored on the database server.

They allow you to:

  • Encapsulate business logic

  • Reduce repeated SQL code

  • Improve performance (precompiled execution)

  • Enhance security (limit direct table access)

  • Accept parameters and return results

 Basic Structure of a Stored Procedure

A stored procedure typically includes:

  • A name

  • Input / output parameters

  • One or more SQL statements

  • Optional control flow (IF, CASE, WHILE)

 MySQL — CREATE PROCEDURE

Call it:

 SQL Server — CREATE PROCEDURE

Execute:

 PostgreSQL — CREATE PROCEDURE

PostgreSQL supports both functions and procedures.
Procedures use CALL.

Call it:

Stored Procedure With Output Parameter (SQL Server)

Use it:

 Stored Procedure With Multiple Queries (MySQL)

Returns two result sets.

 Stored Procedure With Loops & Logic (PostgreSQL)

 Modify or Drop Stored Procedures

MySQL / SQL Server:

PostgreSQL:

 Best Practices

  •  Use parameters to avoid SQL injection
  •  Keep stored procedures small and modular
  •  Include error handling (TRY/CATCH in SQL Server, EXCEPTION in PostgreSQL)
  •  Avoid dynamic SQL unless necessary
  •  Use version control for stored procedure code
  •  Return values in a consistent format

 When to Use Stored Procedures

  •  Business rules executed frequently
  •  Complex multi-step operations
  •  Audit logging
  •  Batch processing
  •  Reducing network traffic (server-side execution)

Avoid for:

  • Simple SELECT queries

  • Logic better served in the application layer

You may also like...