Alter Stored Procedures

How to Alter Stored Procedures in MySQL

MySQL does not provide a direct ALTER PROCEDURE statement. If you need to modify a stored procedure, you must drop and recreate it.

1. Steps to Modify a Stored Procedure in MySQL

Since MySQL does not allow altering stored procedures, follow these steps to update one:

1️⃣ Retrieve the existing stored procedure code
2️⃣ Modify the code as needed
3️⃣ Drop the existing stored procedure
4️⃣ Recreate the modified stored procedure

2. Steps in Detail

Step 1: View the Existing Procedure

Before altering a stored procedure, retrieve its current definition.

SHOW CREATE PROCEDURE procedure_name;

📌 Example

SHOW CREATE PROCEDURE get_users;

✔ This will return the SQL definition of the get_users procedure.

Step 2: Modify the Procedure

Copy the retrieved procedure definition and make the necessary changes.

Step 3: Drop the Existing Procedure

Before recreating the procedure, drop the existing one:

DROP PROCEDURE IF EXISTS procedure_name;

📌 Example

DROP PROCEDURE IF EXISTS get_users;

✔ This prevents errors if the procedure does not exist.

Step 4: Recreate the Procedure

Now, recreate the modified stored procedure.

📌 Example – Assume we modify get_users to filter active users only:

DELIMITER //

CREATE PROCEDURE get_users()
BEGIN
    SELECT * FROM users WHERE status = 'active';
END //

DELIMITER ;

✔ This redefines the stored procedure to return only active users.

3. Key Takeaways

✔ MySQL does not support ALTER PROCEDURE
✔ You must drop and recreate the procedure to modify it
✔ Always retrieve and save the procedure definition before modifying it
✔ Use SHOW CREATE PROCEDURE to get the current procedure code

Would you like help with a specific procedure modification? 🚀

Souy Soeng