Troubleshooting MySQL Error 1303: Resolving Stored Procedure and Function Conflicts

MySQL Error 1303 – SQLSTATE: 42000 (ER_SP_ALREADY_EXISTS) is an error that occurs when you attempt to create a stored procedure or function that already exists with the same name in the database. The error message “%s %s already exists” indicates a naming conflict, where %s placeholders represent the type (PROCEDURE or FUNCTION) and the name of the routine.

Understanding the Error

In MySQL, stored procedures and functions are objects that encapsulate a set of SQL statements for reuse. Each stored procedure or function within a database must have a unique name. Error 1303 is encountered when you try to create a new routine that has the same name as an existing one in the same database.

Diagnosing the Problem

To resolve this error, you need to:

  1. Check Existing Routines: Use SHOW PROCEDURE STATUS; or SHOW FUNCTION STATUS; to list all stored procedures or functions in the current database. Look for the name that is causing the conflict.
  2. Determine If Overwriting Is Intended: Decide if you meant to replace the existing routine with a new definition.

Fixing the Error

Here are steps to correct Error 1303 based on your intentions:

  1. Rename the New Routine: If you want to keep both the existing and new routines, simply rename the new one: CREATE PROCEDURE new_procedure_name() BEGIN -- Procedure body END;
  2. Drop the Existing Routine: If you intend to replace the existing routine with the new one, drop the existing one first: DROP PROCEDURE IF EXISTS existing_procedure_name; CREATE PROCEDURE existing_procedure_name() BEGIN -- New procedure body END; Replace PROCEDURE with FUNCTION as appropriate if you are dealing with functions.
  3. Use Conditional Creation: To avoid the error, you can use the IF NOT EXISTS clause when creating a routine. However, note that this syntax is not supported for stored procedures or functions in MySQL. Instead, you can conditionally drop the existing routine as shown above before creating the new one.


  • Always check if the routine is in use before dropping it to avoid breaking applications that depend on it.
  • Consider using versioning or different naming conventions for routines if they are frequently updated or replaced.
  • Make sure you have the necessary privileges to create or drop stored procedures or functions in the database.
  • Keep a backup of the routine definitions, especially if you are replacing them, in case you need to revert changes.

By carefully checking for existing routines, deciding on the appropriate action, and executing the correct SQL statements, you can resolve MySQL Error 1303 and manage your stored procedures and functions effectively.

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