Fix mysqli_num_rows() Error in PHP

In PHP, the function mysqli_num_rows() is used to retrieve the number of rows in a result set. If you encounter an error while using this function, there are a few possible solutions that may help.

1. Check if the SQL query statement is correct: Firstly, make sure that your SQL query statement is accurate. You can test the query statement in a database management tool to see if it returns the expected results. If there are errors in the query statement, it may cause the mysqli_num_rows() function to not work properly. Ensure that your query statement does not have spelling errors, syntax errors, etc.
2. Check if the result set exists: Before calling the mysqli_num_rows() function, make sure you have executed a query and obtained the result set through the mysqli_query() function. If you have not executed the query correctly or the result set is empty, calling the mysqli_num_rows() function will result in an error. You can use the return value of the mysqli_query() function to verify if the query operation was successful.
3. Check if the database connection is correct: Before using the mysqli_num_rows() function, you need to connect to the database. Make sure you are using the correct hostname, username, password, and database name when connecting to the database. You can establish the database connection using the mysqli_connect() function or the mysqli_init() and mysqli_real_connect() functions. If the database connection fails, it may cause the mysqli_num_rows() function to not work properly.
4. Check your PHP version and MySQL extension: Make sure you are using a PHP version that supports the MySQLi extension. If your PHP version is older, it may not support the MySQLi extension, causing issues with the mysqli_num_rows() function. You can check the PHP version and MySQLi extension information by using the phpinfo() function in your PHP code.

I hope these solutions can help you resolve the issue. If the problem persists, please provide more error information and code snippets so that we can better assist you in resolving the issue.