Error
Error Code:
2031
MySQL Error 2031: No Data for Prepared Statement
Description
Error 2031, "No data supplied for parameters in prepared statement," indicates a client-side issue where a prepared statement is executed without providing data for all its required parameters. This typically occurs when the application code fails to bind values to parameter placeholders before attempting to execute the SQL query.
Error Message
No data supplied for parameters in prepared statement
Known Causes
3 known causesUnbound Parameters
A prepared statement was executed without binding all parameters to their respective placeholders, or attempting to execute before any parameters were bound.
Mismatched Parameter Count
The number of parameters supplied for binding does not match the number of parameter placeholders ('?') defined in the SQL query.
Premature Execution
The prepared statement was executed before the necessary `bind_param()` or equivalent function calls were made to provide data for the placeholders.
Solutions
3 solutions available1. Verify Parameter Count in Binding easy
Ensure the number of bound parameters matches the placeholders in the SQL statement.
1
Review your SQL query and count the number of question mark (?) placeholders used for parameters.
2
Examine the code that prepares and executes the statement. Ensure that the number of values you are binding to the prepared statement exactly matches the number of placeholders in the SQL query.
Example in PHP:
// Incorrect: 2 placeholders, but only 1 value bound
$stmt = $pdo->prepare('SELECT * FROM users WHERE id = ? AND status = ?');
$stmt->execute([1]);
// Correct: 2 placeholders, 2 values bound
$stmt = $pdo->prepare('SELECT * FROM users WHERE id = ? AND status = ?');
$stmt->execute([1, 'active']);3
If using a different programming language, consult its documentation for the specific API used for binding parameters to prepared statements and verify the count.
2. Check for Missing or Null Values easy
Confirm that all intended parameter values are present and not null when binding.
1
Inspect the variables or data structures you are using to supply values for the prepared statement's parameters.
2
Ensure that no required parameter is inadvertently omitted or assigned a `NULL` value if the SQL query expects a non-null value for that parameter.
Example in Python:
# Potential Issue: 'email' might be None if not fetched correctly
user_id = 123
username = 'john_doe'
email = None # This could cause the error if email is a required parameter
cursor.execute("INSERT INTO users (id, username, email) VALUES (?, ?, ?)", (user_id, username, email))
# Corrected approach: Ensure all values are valid
user_id = 123
username = 'john_doe'
email = 'john.doe@example.com'
cursor.execute("INSERT INTO users (id, username, email) VALUES (?, ?, ?)", (user_id, username, email))3
Add logging or debugging statements to track the values of parameters just before they are bound to the prepared statement.
3. Review Prepared Statement Logic in Application Code medium
Thoroughly examine the application's code that constructs and executes prepared statements.
1
Identify all instances in your application where `PREPARE`, `EXECUTE`, and `BIND` (or equivalent) operations are performed with MySQL prepared statements.
2
Carefully trace the data flow. Understand how the values for the parameters are determined. This might involve looking at user input, database lookups, or internal application logic.
3
Look for conditional logic that might lead to fewer parameters being bound than expected by the SQL statement. For example, if a parameter is only bound under certain conditions, and those conditions are not met, the error can occur.
Example in Java (JDBC):
String sql = "UPDATE products SET price = ?, description = ? WHERE id = ?";
PreparedStatement pstmt = connection.prepareStatement(sql);
double newPrice = 19.99;
String newDescription = "Updated product details";
int productId = 456;
// Potential issue: if 'newDescription' can be null and the SQL expects it
// Or if the logic that sets 'newDescription' fails to assign a value.
pstmt.setDouble(1, newPrice);
// If newDescription is null and the SQL requires a non-null value, this can be problematic.
pstmt.setString(2, newDescription);
pstmt.setInt(3, productId);
// Ensure all parameters are correctly set before execution.
pstmt.executeUpdate();4
Use debugging tools or add extensive logging to step through the code and observe the values of parameters at each stage of preparation and execution.