Error
Error Code:
1312
MySQL Error 1312: Procedure Result Set Context Error
Description
Error 1312 occurs when a MySQL stored procedure attempts to return a result set (e.g., from a SELECT statement) in an execution context where it is not permitted. This often happens when a procedure is invoked from a function, a trigger, or another procedure that itself is part of a restricted operation.
Error Message
PROCEDURE %s can't return a result set in the given context
Known Causes
3 known causesProcedure Called from a Function
MySQL functions are designed to return a single scalar value and cannot execute stored procedures that produce result sets.
Procedure Called from a Trigger
Triggers have execution limitations and generally cannot call stored procedures that return result sets, as there's no client to receive them.
Nested Procedure Result Set
A stored procedure called by another procedure might attempt to return a result set when the calling procedure or its context doesn't support it.
Solutions
3 solutions available1. Remove SELECT Statement from Stored Procedure easy
The most common cause is a SELECT statement directly within the stored procedure that isn't part of an INSERT, UPDATE, DELETE, or other DML that implicitly returns rows.
1
Identify the stored procedure that is causing the error. The error message usually specifies the procedure name.
2
Examine the stored procedure's code for any standalone `SELECT` statements that are not intended to return a result set to the caller (e.g., `SELECT column INTO variable`, or `SELECT ... FROM ... WHERE condition` that doesn't directly feed into another operation).
3
Remove or comment out the `SELECT` statement if it's not required to return a result set. If the `SELECT` is intended to fetch data for use within the procedure, ensure it's either selecting into variables or is part of a larger DML statement.
-- REMOVE OR MODIFY THIS SELECT STATEMENT
-- SELECT column1, column2 FROM my_table WHERE some_condition;4
Re-create the stored procedure with the modified code.
DELIMITER $$
CREATE PROCEDURE your_procedure_name(...)
BEGIN
-- ... your other procedure logic ...
END$$2. Use CALL for Procedures Returning Result Sets easy
When a stored procedure is designed to return a result set (e.g., it contains a SELECT statement that is intended to be the output), it must be invoked using the `CALL` statement.
1
Ensure the stored procedure you are calling is designed to return a result set. This typically means it contains a `SELECT` statement as one of its last operations.
2
Instead of executing the procedure directly (e.g., `SELECT your_procedure_name();`), use the `CALL` statement.
CALL your_procedure_name();3
If you are using a client tool that doesn't automatically handle `CALL` correctly, ensure it's configured to execute statements as `CALL` when appropriate. For example, in MySQL Workbench, you would typically select the procedure and then click 'Execute' which would generate the `CALL` statement.
3. Adjust Client Application Logic medium
The error might occur if your application code is trying to execute a stored procedure in a context where it expects a single value or a different type of return, but the procedure is returning a result set.
1
Review the code in your application that is invoking the stored procedure. Determine how the result of the procedure is being handled.
2
If the stored procedure is intended to return a result set, ensure your application code is prepared to receive and process it. This might involve using methods that handle multiple rows and columns, rather than methods expecting a single scalar value.
Example (Python with mysql.connector):
cursor.execute("CALL your_procedure_name()")
results = cursor.fetchall()3
If the stored procedure is NOT intended to return a result set, follow Solution 1 to modify the procedure. If it IS intended to return a result set but your application is trying to treat it as a scalar, you may need to adjust your application's expectations or how it calls the procedure.