Why can't I use $mysqli->query in a custom function?

Question

Answer 1

There is something wrong with your usage~~

The prerequisite for using $mysqli->query() is: you have created the $mysqli object. I wonder if you have created this object in the dbconfigs.php file?

Also, you used mysqli_fetch_array() below. This is a typical process-oriented statement. I really don’t understand how you want to call the data?

If you want to use object-oriented, please use it like this:

$mysqli = new mysqli($host,$userName,$password,$dbName);
if ($mysqli->connect_errno){
    die('Error Connected'.$mysqli->connect_error;
}
$result = $mysqli->query('SELECT * FROM table_name');
if ($result && $result->num_rows > 0){
while($row = $result->fetch_array(MYSQLI_ASSOC)){
   //输出数据
 }
 $result->free_result();
}
$mysqli->close();

If it is process-oriented, please modify the above code:

$conn = mysqli_connect($host,$userName,$password,$dbName);
if (mysqli_connect_errno($conn)){
    die('Error Connected'.mysqli_connect_error($conn);
}
$result = mysqli_query('SELECT * FROM table_name');
if ($result && mysqli_num_rows($conn,$result) > 0){
while($row = mysqli_fetch_array($result,MYSQLI_ASSOC)){
   //输出数据
 }
 mysqli_free($result);
}
mysqli_close($conn);

Please do not mix object-oriented and process-oriented.

PHP Chinese website has tutorials for these two parts:

http://www.php.cn/course/653.html (MySQLi object-oriented)

http://www.php.cn/course/653 .html (MySQLi is process-oriented)