在计数器达到0之前停止循环

For now the no of vacancy is 3 for that company. I want it to stop subtracting at 0.

This is my code:

$result4 = mysqli_query($con,"SELECT no_of_vacancy FROM job_details WHERE jobscope= 'Information Technology' AND job_title='Oak 3 Films Pte Ltd (Sales Marketing Department)';");

$result5 = mysqli_query($con, "SELECT COUNT(company) FROM student_details WHERE jobscope1 = 'myJobScope' AND company = 'myCompany';");
while ($row5 = mysqli_fetch_assoc($result5))
{
   $result6 = mysqli_query($con, "UPDATE `job_details` SET `no_of_vacancy`= `no_of_vacancy` - 2 WHERE `job_title` = 'myCompany';"));
}

I want to subtract a value from a company's no of vacancy once a student is assigned to it.

Company | Vacancy|

ABC     | 3 

I want it to show 0 once 3 students is assigned to it. For now it goes till -1 every time the code runs.

You stop While loop with break; You can stop everything with exit;

What is the point of this code ?

To stop loop execution:

while ($row5 = mysqli_fetch_assoc($result5))
{
   $result6 = mysqli_query([...]);
   if(condition)
      break;
}

To skip current execution:

while ($row5 = mysqli_fetch_assoc($result5))
{
   if(condition)
       continue;
   $result6 = mysqli_query([...]);
}

Did you already try using "break"?

You could for example use your code in the following manner:

$result4 = mysqli_query($con,"SELECT no_of_vacancy FROM job_details WHERE jobscope= 'Information Technology' AND job_title='Oak 3 Films Pte Ltd (Sales Marketing Department)';");

$result5 = mysqli_query($con, "SELECT COUNT(company) FROM student_details WHERE jobscope1 = 'Information Technology' AND company = 'Oak 3 Films Pte Ltd (Sales Marketing Department)';");
while ($row5 = mysqli_fetch_assoc($result5))
{


$result6 = mysqli_query($con, "UPDATE `job_details` SET `no_of_vacancy`= `no_of_vacancy` - 2 WHERE `job_title` = 'Oak 3 Films Pte Ltd (Sales Marketing Department)';"));

if ($result6 == 0)
{
break;
}

I hope it could help.