If you are a developer working with PHP and MySQL, you may have encountered the mysqli_num_rows() expects parameter 1 to be mysqli_result error message. This error occurs when the mysqli_query() function fails to return a result set, and you try to pass it to the mysqli_num_rows() function. In this guide, we will provide a step-by-step solution to fix this error.
Step 1: Check Your MySQL Connection
The first step in troubleshooting this error is to check your MySQL connection. Make sure that you have established a connection to your MySQL database by using the mysqli_connect() function. Here's an example of how to establish a MySQL connection:
$host = "localhost";
$user = "username";
$password = "password";
$database = "database_name";
$conn = mysqli_connect($host, $user, $password, $database);
if (!$conn) {
die("Connection failed: " . mysqli_connect_error());
}
Step 2: Verify Your SQL Query
The next step is to verify your SQL query. Make sure that your SQL query is correct and that it returns a result set. Here's an example of how to execute an SQL query:
$sql = "SELECT * FROM table_name";
$result = mysqli_query($conn, $sql);
if (!$result) {
die("Query failed: " . mysqli_error($conn));
}
Step 3: Check Your Result Set
The final step is to check your result set. Make sure that your result set is not empty before passing it to the mysqli_num_rows() function. Here's an example of how to check your result set:
if (mysqli_num_rows($result) > 0) {
// Your code here
} else {
echo "No results found";
}
By following these steps, you should be able to fix the mysqli_num_rows() expects parameter 1 to be mysqli_result error.
FAQ
What is mysqli_num_rows()?
mysqli_num_rows() is a PHP function that returns the number of rows in a result set.
What is mysqli_query()?
mysqli_query() is a PHP function that executes an SQL query and returns a result set.
Why am I getting the mysqli_num_rows() expects parameter 1 to be mysqli_result error?
You are getting this error because the mysqli_query() function failed to return a result set, and you are trying to pass it to the mysqli_num_rows() function.
What is a result set?
A result set is a set of rows returned by an SQL query.
How can I prevent this error from occurring?
You can prevent this error from occurring by verifying your MySQL connection, verifying your SQL query, and checking your result set before passing it to the mysqli_num_rows() function.