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Description

MySQL Error 2034, 'Invalid parameter number', indicates a mismatch between the number of parameter placeholders in a SQL query (e.g., `?` or `:param`) and the actual number of parameters provided. This typically occurs when executing prepared statements or calling stored procedures with an incorrect argument count, preventing query execution.

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Error Message

Invalid parameter number

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Known Causes

3 known causes

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Placeholder/Parameter Mismatch

The number of parameter placeholders in a prepared SQL statement does not match the number of parameters supplied when binding values.

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Incorrect Stored Procedure Arguments

A stored procedure or function is called with a different number of arguments than it expects in its definition.

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Dynamic Query Construction Errors

When constructing SQL queries dynamically, the code might incorrectly count or assign parameters to placeholders, leading to a mismatch.

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Solutions

3 solutions available

1. Verify Parameter Count in Prepared Statements easy

Ensure the number of placeholders in your SQL query matches the number of parameters provided.

1

Examine the SQL query being executed. Look for placeholders, typically represented by `?` or named parameters (e.g., `:param_name`).

SELECT * FROM users WHERE id = ? AND status = ?

2

In your application code, verify that the number of values you are binding to these placeholders exactly matches the number of placeholders in the query.

statement.bind_param('ii', $userId, $status); // Example in PHP, 'ii' indicates two integers

3

If using named parameters, ensure each named parameter in the SQL has a corresponding named parameter in your bind call.

statement.bind_param(':userId', $userId); // Example in Python/SQLAlchemy

2. Check for Unused or Missing Placeholders medium

Identify if you have placeholders in your query that are not being bound, or if you've missed binding a required placeholder.

1

Carefully review your SQL query for any stray `?` or named parameter symbols.

SELECT name, email FROM customers WHERE order_id = ? AND completed = ? AND shipped_date IS NULL

2

Compare this count to the number of `bind_param` or equivalent calls in your application code. Ensure every placeholder has a corresponding bind.

// In your application code, ensure you have 3 bind calls for the above query.

3

Conversely, check if you are binding more parameters than there are placeholders in the SQL. This is also a common cause of this error.

// Incorrect: Binding 4 parameters when the query only has 3 placeholders.

3. Inspect Dynamic Query Construction Logic advanced

If your SQL query is built dynamically, ensure the placeholder count is correctly managed as conditions change.

1

If you are building SQL strings programmatically, pay close attention to how `?` or named parameters are added based on conditional logic.

sql = "SELECT * FROM products WHERE 1=1";
if (category) {
  sql += " AND category = ?";
  params.push(category);
}
if (price_range) {
  sql += " AND price BETWEEN ? AND ?";
  params.push(price_range.min);
  params.push(price_range.max);
}

2

Log the generated SQL query and the list of parameters *before* execution. This is crucial for debugging dynamic queries.

// Log the query and parameters here

3

Manually verify that the number of `?` or named parameters in the logged SQL string matches the number of items in your logged parameter array/list.

console.log("Generated SQL: ", sql);
console.log("Parameters: ", params);

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Related Errors

5 related errors

MySQL Error 2034: Mismatched Query Parameters