Call a PHP function inside of a while loop - php

Question

I have a function which gets a particular set of users from a table where a particular WHERE condition is meet.
I need to send each of them a message.
So, I used another function to send the message. And called that function inside he following while loop
while($user= mysqli_fetch_assoc($users_set)){
send_message($user['email']);
}
So, the problem is, the function is called only just one time. (Only with the last value of the loop)
How to fix this problem and make the function called with each value of the loop...
This is the full code...
$query = "SELECT * ";
$query .= "FROM user ";
$query .= "WHERE confirmed = 0";
$user_set = mysqli_query($db_conx, $query);
confirm_query($user_set);
while($user = mysqli_fetch_assoc($user_set)){
send_message($user['email']);
}
Here is the send message function....
function send_message($email){
global $db_conx;
$invitee_user = get_user_by_email($email);
$query5 = "INSERT INTO notification(";
$query5 .= "description, user_id";
$query5 .= ") VALUES(";
$query5 .= "'You have been confirmed'";
$query5 .= ", {$invitee_user['id']}";
$query5 .= ")";
$result5 = mysqli_query($db_conx, $query5);
if($result5){
//$_SESSION["message"] = "Notification sent". \mysqli_error($db_conx);
return "OK";
}else{
//$_SESSION["message"] = "Failed to send notification". mysqli_error($db_conx);
}
}
Here is the code for confirm_query()
function confirm_query($result_set){
if(!$result_set){
die("Fatal Error Occured : Database Query Failed Report this error");
}
}

Answer 1

I would just boil this down to one query and get rid of all the looping stuff
INSERT INTO notification (description, user_id)
SELECT 'You have been confirmed', user_id
FROM user
WHERE confirmed = 0
Your current logic is really convoluted.
You query the user table to get the user email field, then pass that email as parameter to your function only to then turn around and (I presume) look up the user ID based on email (when you already had this information from your initial query), then you make insert.
This means that for every record you return from first query, you need to do 2 queries to insert to the notification table. So if you had 100 results you would end up doing a total of at least 201 queries to complete the insertions.
Using my approach you make 1 query regardless of how many rows are affected.
One takeaway that you should get from this is that, anytime you see yourself trying to do some sort of nested querying, you should recognize this as an anti-pattern (a coding pattern that you do not want to typically use). There is usually a better approach that can be taken if you rethink how you are writing your queries.