PHP MYSQL Error when calling multiple Stored Procedures - php

Question

I am having difficulty calling and displaying the content when I call a procedure more than once in a page. I am trying to display two separate record sets from two different SP calls for MYSQL. I can display the first call but the second fails. I'm not sure what I am doing wrong but perhaps someone can kind help?
I keep getting the error when I call the second procedure:
Error calling SPCommands out of sync; you can't run this command now
I'm running on windows
Code below... PHP
// First call to SP
$page = 2;
$section = 1;
include("DatabaseConnection.php"); //general connection - works fine
$sql = 'CALL GetPageContent("'.$page.'", "'.$section.'")';
$result = mysqli_query($conn, $sql) or die('Error calling SP' .mysqli_error($conn));
while($row=mysqli_fetch_assoc($result))
{
// DO STUFF< REMOVED TO MAKE READING CLEARER
}
mysqli_free_result($result);
//SECOND CALL BELOW
$section = 2; // change parameter for different results
$sql = 'CALL GetPageContent("'.$page.'", "'.$section.'")';
$result = mysqli_query($conn, $sql) or die('Error calling SP' .mysqli_error($conn));
while($row=mysql_fetch_assoc($result))
{
// DO STUFF< REMOVED TO MAKE READING CLEARER
}

Answer 1

To fix the problem, remember to call the next_result() function on the mysqli object after each stored procedure call. See example below:
<?php
// New Connection
$db = new mysqli('localhost','user','pass','database');
// Check for errors
if(mysqli_connect_errno()){
echo mysqli_connect_error();
}
// 1st Query
$result = $db->query("call getUsers()");
if($result){
// Cycle through results
while ($row = $result->fetch_object()){
$user_arr[] = $row;
}
// Free result set
$result->close();
$db->next_result();
}
// 2nd Query
$result = $db->query("call getGroups()");
if($result){
// Cycle through results
while ($row = $result->fetch_object()){
$group_arr[] = $row;
}
// Free result set
$result->close();
$db->next_result();
}
else echo($db->error);
// Close connection
$db->close();
?>

Answer 2

if you are calling more than one procedure on a single script page, you should call mysqli_next_result($connection_link) before calling another procedure.
consider below sample code block:
<?php
$data = new \stdClass();
require('./controller/dbController.php');
$query = 'CALL getActiveProductCount()';
$result = mysqli_query($con, $query);
$result = mysqli_fetch_assoc($result);
$data->active_product = $result['count'];
mysqli_next_result($con); // required to perform before calling the procedure again
$query = 'CALL getPurchasedProductCount()';
$result = mysqli_query($con, $query);
$result = mysqli_fetch_assoc($result);
$data->purchased = $result['count'];
mysqli_next_result($con);