mysql to check if value is more than 0 - php

Question

Here's my code. Actually it run without error but it always enter the first condition even though the value in mysql is more than 0 say for example is 10.
<?php
session_start();
$loginuser = $_SESSION['result'];
$con=mysqli_connect("localhost","root","","leavecalendar");
// Check connection
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$sql="SELECT leavecount from employee WHERE username = $loginuser[username]";
$resource = mysql_query($sql);
if ($resource == 0) {
echo "ajsdjsdasjd"; <----always enters here
}
else
{
header("insert.php");
}
mysqli_close($con);
?>

Answer 1

First off, you are mixing api's. Dont mix mysqli_* and mysql_*. Just stick with mysqli_*.
$con = mysqli_connect("localhost","root","","leavecalendar"); // mysqli
$resource = mysql_query($sql); // mysql
Second, since you are using mysqli_* now, just use prepared statements.
$sql="SELECT leavecount from employee WHERE username = $loginuser[username]";
Third, dont compare the result set to zero, instead, check how many rows did the result return.
$resource = mysqli_query($con, $sql);
if ($resource == 0) {
Consider this example:
session_start();
if(isset($_SESSION['result'])) {
$mysqli = mysqli_connect("localhost","root","","leavecalendar");
$loginuser = $_SESSION['result'];
$stmt = $mysqli->prepare("SELECT leavecount from employee WHERE username = ?");
$stmt->bind_param("s", $loginuser);
$stmt->execute();
if($stmt->num_rows > 0) {
// if it has results
header("Location: insert.php");
} else {
// if it has NO results
}
}

Answer 2

Problems
1) You can not use
mysql_query($query)
For mysqli
2)
"SELECT leavecount from employee WHERE username = $loginuser[username]"
The username should be single quoted or double quoted.
For ex: "SELECT leavecount from employee WHERE username = 'dineshrawat'";
Solution
<?php
session_start();
$loginuser = $_SESSION['result'];
$con=mysqli_connect("localhost","root","","leavecalendar");
// Check connection
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$sql="SELECT leavecount from employee WHERE username = $loginuser[username]";
$resource = mysqli_query($con, $sql);
if ($resource == 0) { // If there is no record in result set
echo "No record found";
}
else
{
header("insert.php");
}
mysqli_close($con);
?>