Insert query inside a loop with sleep() function not working - php

Question

I have a while loop with a sleep() function given below :
$employee = mysqli_query( $conn , "SELECT emp_id,emp_name FROM employee
WHERE DATE(datetime) = '$date' " );
if(mysqli_num_rows($employee) > 0){
while ($row = mysqli_fetch_array($employee)) {
$emp_id = $row['emp_id'];
$emp_name = $row['emp_name'];
$number = mysqli_query( $conn ,"SELECT phone_number FROM emp_phone_number
WHERE emp_id = '$emp_id' ");
if(mysqli_num_rows($number) > 0){
while ($row2 = mysqli_fetch_array($number)) {
sleep(2);
}
}
mysqli_query($conn , " INSERT INTO `emails`(`emp_id`, `email`) VALUES ('$emp_id','hello') ");
}
}
The Insert query is working fine without the sleep() function. But when I enable the sleep() function it does not working. Please suggest me the reason.

Answer 1

Where do you open Database connection using mysqli_connect() ? It may be due to Mysql connection timeout as you have sleep of every 2 second. Try using mysqli_connect() before the mysqli_query("Insert Query"); it will work.

Answer 2

The PHP sleep function takes a int argument which is seconds the execution should sleep.
You choose to sleep 2 seconds for each number of each employee.
I would think that the reason your code don't "work" is cause your execution time is so long due to the sleep call that you never see it finish.
Honestly, I cant see why you would ever want to use the sleep function in this case, and it looks quite strange that you just want to sleep a few seconds if a employee have a number or more...

Answer 3

Several people have suggested timeout errors. That seems likely. I would try catching any exceptions to find out what is really happening
$employee = mysqli_query( $conn , "SELECT emp_id,emp_name FROM employee
WHERE DATE(datetime) = '$date' " );
try{
if(mysqli_num_rows($employee) > 0){
while ($row = mysqli_fetch_array($employee)) {
$emp_id = $row['emp_id'];
$emp_name = $row['emp_name'];
$number = mysqli_query( $conn ,"SELECT phone_number FROM emp_phone_number
WHERE emp_id = '$emp_id' ");
if(mysqli_num_rows($number) > 0){
while ($row2 = mysqli_fetch_array($number)) {
sleep(2);
}
}
mysqli_query($conn , " INSERT INTO `emails`(`emp_id`, `email`) VALUES ('$emp_id','hello') ");
}
}
}
catch(\Exception $e){
die($e->getMessage());
}