PHP is updating a database index that doesn't exist - php

Question

On my main page, when someone signs-in, i have jQuery using AJAX to 'talk' to a PHP file, and the same for when they sign-out. But, when they sign out, it is supposed to update a database index with the time they left. If they database entry for their last name doesn't exist (meaning, they didn't sign-in), it is supposed to return an error. Instead, the PHP file is saying that it IS updating a non-existant database index. i am using IF statements to achieve this. and for some reason it thinks the index does exist. I've checked the database that it is writing to and the indexes it's supposed to be updating don't exist.
Here's my code:
if ($Type == 1)
{
$mysqli = new mysqli("localhost","----","----", "----");
if (!$mysqli)
$Type = 3;
$Select = $mysqli->query("SELECT Time_Out FROM " . $Date . " WHERE Last_Name = '" . $LName . "'");
$Row = $Select->fetch_assoc();
$Row2 = $Row['Time_Out'];
if ($Row2 !== "-1") $Type = 4;
if ($Type == 1)
{if ($mysqli->query("UPDATE " . $Date . " SET Time_Out='" . $Time . "' WHERE Last_Name='" . $LName . "'"))
{}
else
{$Type = 5;}
}
$Select = $mysqli->query("SELECT Time_In FROM " . $Date . " WHERE Last_Name='" . $LName . "'");
$Row = $Select->fetch_assoc();
$Row2 = $Row['Time_In'];
$Time2 = explode(":",$Row2);
$Hour2 = $Hour - $Time2[0];
if ($mysqli->query("SELECT Hours FROM Names WHERE Last_Name='" . $LName . "'"))
{$Select = $mysqli->query("SELECT Hours FROM Names WHERE Last_Name='" . $LName . "'");
$Row = $Select->fetch_assoc();
$Row3 = $Row['Hours'];
$Auto += 1;}
$Time3 = 60-$Time2[1];
if ($Hour != 21) $Time4 = $Min;
$Time5 = $Time3+$Time4;
if ($Time2[0]+1 != $Hour)
{$Time5 = $Time5+60;}
$Total = $Time5+intval($Row3);
if ($Type == 1)
{
if ($mysqli->query("UPDATE Names SET Hours = '" . $Total . "' WHERE Last_Name = '" . $LName . "'"))
{$Auto += 1;}
else
{$mysqli->query("INSERT INTO Names (Last_Name, First_Name, Hours) VALUES ('" . $LName . "', '" . $FName . "', '" . $Total . "')");}
}
$mysqli->close();
}
if ($Type == 1) echo "Thank you " . $FName . " " . $LName . " for signing out! See you next time!";
if ($Type == 2) echo "The entered Student ID# is invalid. Please try again!";
if ($Type == 3) echo "An unexpected error has occured. Please try again!";
if ($Type == 4) echo "You have already signed out today!" . $Auto;
if ($Type == 5) echo "You didn't sign in today.";

Answer 1

The UPDATE sql statement will return true, even if it doesn't find any matches (it still runs correctly, it just updates 0 rows).
Change this:
if ($Type == 1)
{if ($mysqli->query("UPDATE " . $Date . " SET Time_Out='" . $Time . "' WHERE Last_Name='" . $LName . "'"))
{}
else
{$Type = 5;}
}
To this:
if ($Type == 1) {
if ($mysqli->query("SELECT * FROM " . $Date . " WHERE Last_Name='" . $LName . "'")->num_rows > 0)
$mysqli->query("UPDATE " . $Date . " SET Time_Out='" . $Time . "' WHERE Last_Name='" . $LName . "'");
else
$Type = 5;
}
You run the select query to first determine if the record exists (if num_rows property of the result is > 0) and based on that either update the record or set your return value to 5.