How to run multiple query on single save button? - php

Question

When I click on the save button only all_university table updates but the all_colleges table has not been updated. How can I update two tables on one save button?
<?php
if(isset($_POST['save'])) {
$chk = implode(",", $_POST['company_name']);
$sql = "update all_university set placement = '$chk' where university_name = '".$_POST['university_name']."'";
$sql = "update all_colleges set placement = '$chk' where college_name = '".$_POST['college_name']."'";
$value = mysqli_multi_query($link,$sql);
if($value == true){
$msg .="<h5 style='color:green'>Successfull</h5>";
} else {
$msg .="<h5 style='color:red'>Error!</h5>";
}
}
?>

Answer 1

It doesn't matter how many queries you have. Just run them all one by one.
Besides, you should be using prepared statements.
<?php
if(isset($_POST['save'])) {
$chk = implode(",", $_POST['company_name']);
$sql = "update all_university set placement = ? where university_name = ?";
$stmt = $link->prepare($sql);
$stmt->bind_param("ss", $chk, $_POST['university_name']);
$stmt->execute();
$sql = "update all_colleges set placement = ? where college_name = ?";
$stmt = $link->prepare($sql);
$stmt->bind_param("ss", $chk, $_POST['college_name']);
$stmt->execute();
$msg .="<h5 style='color:green'>Successfull</h5>";
}
DO NOT use mysqli_multi_query(). It will do you no good and won't work the way you think.

Answer 2

If you want to use the multi-query function, you have to concatenate the two query strings:
$sql = "update all_university set placement = '$chk' where university_name = '".$_POST['university_name']."';";
$sql .= "update all_colleges set placement = '$chk' where college_name = '".$_POST['college_name']."'";
And then execute mysqli_multi_query.
Or, as Rory already mentioned, just query twice using the normal mysqli_query function.
But you should really look into prepared statements as you are vulnerable to SQL injection!

Answer 3

Separate both query with semicolon (;)
$sql = "update all_university set placement = '$chk' where university_name = '".$_POST['university_name']."';";
$sql = "update all_colleges set placement = '$chk' where college_name = '".$_POST['college_name']."'";
Then, Append Both Query.
$sql = "update all_university set placement = '$chk' where university_name = '".$_POST['university_name']."'";
$sql .= "update all_colleges set placement = '$chk' where college_name = '".$_POST['college_name']."'";
Execute it.
$value = mysqli_multi_query($link,$sql);
The mysqli_multi_query() function performs one or more queries against
the database. The queries are separated with a semicolon.