Error
Error Code:
1327
MySQL Error 1327: Undeclared Variable in Stored Program
Description
This error indicates that a variable was used within a stored program (like a procedure, function, or trigger) without being properly declared. MySQL requires all local variables to be explicitly defined using the `DECLARE` statement before they can be assigned or referenced.
Error Message
Undeclared variable: %s
Known Causes
3 known causesMissing Variable Declaration
A variable was referenced in a stored program without a preceding `DECLARE` statement to define its name and data type.
Typo in Variable Name
A variable was declared, but a different, misspelled version of its name was used later, causing MySQL to treat it as an undeclared variable.
Incorrect Variable Scope
Attempting to use a variable outside the block or scope where it was declared, causing it to be treated as undeclared in the current context.
Solutions
4 solutions available1. Declare the Variable Explicitly easy
Ensure all variables used within a stored program are declared using `DECLARE`.
1
Review your stored program (stored procedure, function, or trigger) code.
2
Identify the variable mentioned in the error message. It will be represented by `%s` in the full error.
3
Add a `DECLARE` statement for this variable at the beginning of your stored program, before it's used. Specify its data type.
DECLARE variable_name datatype;
-- Example: DECLARE my_count INT;
-- Example: DECLARE user_status VARCHAR(20);4
Re-run or compile your stored program.
2. Check for Typos in Variable Names easy
Verify that variable names are spelled correctly and consistently throughout the stored program.
1
Examine the stored program code, paying close attention to the variable name causing the error (`%s`).
2
Compare the spelling and case of the variable where it's declared (if declared) and where it's used.
3
Correct any discrepancies in spelling or case.
4
Re-run or compile your stored program.
3. Ensure Variables are Declared in the Correct Scope medium
Confirm that variables are declared within the appropriate block or routine.
1
If your stored program uses nested blocks (e.g., `BEGIN...END` within another `BEGIN...END`), ensure variables are declared in the most immediate enclosing block where they are needed or in the outer block if they are used across multiple inner blocks.
DELIMITER //
CREATE PROCEDURE example_proc()
BEGIN
DECLARE outer_var INT;
SET outer_var = 10;
BEGIN
DECLARE inner_var VARCHAR(50);
SET inner_var = 'hello';
-- outer_var can be accessed here
SELECT outer_var, inner_var;
END;
-- inner_var cannot be accessed here
SELECT outer_var;
END //
DELIMITER ;
2
A variable declared in an inner block is not accessible in an outer block.
3
If a variable needs to be accessed globally within the stored program, declare it in the outermost `BEGIN...END` block.
4
Re-run or compile your stored program after adjusting scope.
4. Verify Correct Syntax for Variable Assignment easy
Ensure that variables are being assigned values using the correct `SET` or `SELECT ... INTO` syntax.
1
Locate where the problematic variable is being assigned a value.
2
If using `SET`, the syntax should be `SET variable_name = value;`.
SET my_variable = 10;3
If assigning from a query result, use `SELECT column_name INTO variable_name FROM table WHERE ...;`.
SELECT COUNT(*) INTO my_count FROM users WHERE status = 'active';4
Ensure there are no missing keywords or incorrect punctuation.
5
Re-run or compile your stored program.