SQL Syntax Error via php - php

Question

I'm kinda new to php, this place has been a great help for me so far! Anyway, I have this code
$month = "
SELECT SUM(`duration`)
FROM `connlist` AS `month_sum`
WHERE `vatsimid` = '$vatsimid'
AND MONTH(atc_online) = " . $pmonth . "
AND YEAR(atc_online) = " . $year . "
";
That's what I get when I echo out $month
SELECT SUM(`duration`)
FROM `connlist` AS `month_sum`
WHERE `vatsimid` = '1070757'
AND MONTH(atc_online) = 07
AND YEAR(atc_online) = 13
When i use this directly into phpMyAdmin, works as a charm, but when I try to do it through a php webpage, I get the syntax error. I'm using php 5.4
Thanks!
Edit: Full Code:
<?php
//open MySQL connection
$mysql = mysqli_connect('host', 'un', 'pass', 'table')
or die ( "MySQL Error: ".mysqli_error() );
//Get and decode residents data
$jsonData = file_get_contents("link");
$phpArray = json_decode($jsonData, true);
//Start Operations
foreach ($phpArray as $key => $value) {
//Get controller hours for today
$vatsimid = $value[vatsimid];
//Get previous month
$pmonth = date("m", strtotime("-35 days") ) ;
$pmonthName = date("M", strtotime("-35 days") ) ;
echo $pmonth;
echo $pmonthName;
//This year or last year?
If (date("M") != "Jan") { //Checks that it's not January of the next year.
$year = date("y");
}
else {
$year = date("y", strtotime("-1 month") );
}
echo $year;
//Search and sum entries during last month
$month = "SELECT SUM(`duration`)
FROM `connlist` AS `month_sum`
WHERE `vatsimid` = '$vatsimid'
AND MONTH(atc_online) = " . $pmonth . "
AND YEAR(atc_online) = " . $year . "";
echo $month;
echo "</br> </br>";
$result = mysqli_query($mysql,$month);
$row = mysqli_fetch_assoc($result);
$month_sum = $row['month_sum'];
echo $month_sum;
//Updates data in atclist
$datainsert = "
UPDATE `atclist`
SET " . $monthName . "=" . $month_sum . "
WHERE vatsimid = " . $vatsimid . "";
$insert = mysqli_query($mysql,$datainsert);
if (!$insert)
{
die('Error: ' . mysqli_error($mysql));
}
}
/*

Answer 1

Did you mean:
SELECT SUM(duration) AS month_sum
FROM connlist
WHERE vatsimid = '1070757' AND MONTH(atc_online) = 07 AND YEAR(atc_online) = 13

Answer 2

It looks like $month_sum variable is not set or empty in your UPDATE query.
You can add single quotes like
$datainsert = "
UPDATE atclist
SET ".$monthName."= '".$month_sum."'
WHERE vatsimid= '".$vatsimid."'";