Why is my mysqli_fetch_array() function throwing an 'Argument #1 must be of type mysqli_result' error and how can I fix it?

Resolving MySQLi Errors: mysqli_fetch_array() Invalid Arguments and Similar Issues

In MySQLi, encountering errors like "mysqli_fetch_array(): Argument #1 must be of type mysqli_result" indicates a failure in executing the SQL query. To resolve this and other similar problems, follow these guidelines:

1. Enable mysqli Error Reporting

Always include mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT); before the mysqli connection to display detailed error messages. PHP will then generate fatal errors for MySQL errors, making the error source clear.

2. Use Prepared Statements

Replace PHP variables in SQL queries with question marks. Execute the query using a prepared statement like $stmt = $mysqli->prepare("SELECT id, description FROM tbl_page_answer_category WHERE cur_own_id = ?");. This prevents syntax errors caused by mismatched tokens or invalid inputs.

3. Check Error Messages

Examine the error message produced by MySQL. It contains the file name, line number, and a detailed explanation of the problem. Focus on understanding the error rather than just finding a quick fix. Make sure the table exists, the query syntax is correct, and that the logic flow reaches the query execution point.

4. Basic Debugging

If the query seems to be executed but produces no results, consider these factors:

• Ensure the query ran without errors.
• Check that the program logic flows correctly to the query execution point.
• Verify that the results are being displayed from the correct database.
• Examine the input data to ensure it matches the database format.

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