my if statement prevents data from being fetched - php

Question

I am working on a small project, and I have code that contains an "if" statement. However, I noticed whenever I fetch data with the value of 0 it does bring it back (var_dump()) but it doesn't display it because I guess the code thinks it's a useless value?
<?php
include_once 'dbh.inc.php';
$sqli = "SELECT datum, v, vo, nav FROM months;";
$result = mysqli_query($conn, $sqli);
$resultCheck = mysqli_num_rows($result);
echo "<table>";
echo "<tr>";
echo "<th>Datum</th>";
echo "<th> Vakantie uren</th>";
echo "<th> Vakantie uren opgennomen </th>";
echo "<th> Nieuw aantal vakantie uren</th>";
echo "</tr>";
if ($resultCheck > 0) {
while ($row = mysqli_fetch_assoc($result)) {
if($row['datum'] AND $row['v'] AND $row['vo'] AND $row['nav']) {
echo "<tr>";
echo "<td>".$row['datum']."</td>";
echo "<td>".$row['v']."</td>";
echo "<td>".$row['vo']."</td>";
echo "<td>".$row['nav']."</td>";
echo "</tr>";
}
}
echo "</table>";
}
?>
please notice the if ($row['datum'] etc.
When I take this piece of code out it renders even the values of 0, however if I end up having values that haven't been filled out (for example u have 5 tables in your database and the user fills 4 in because the fifth one is a useless one for him) it fetches the 5th one back as well and I end up having a very ugly empty spot. It doesn't look very nice.
My question is, is there a possible way to tell php (even with an "if" statement) that the value 0 is a value I want displayed?

Answer 1

If I understand you correctly, You don't want to display the row when there are no values but you want to display it when there are values even if the values are zeros.
Your if statement does not work because 0 = false in php.
Therefore consider modifying your if statement like so:
<?php
include_once 'dbh.inc.php';
$sqli = "SELECT datum, v, vo, nav FROM months;";
$result = mysqli_query($conn, $sqli);
$resultCheck = mysqli_num_rows($result);
echo "<table>";
echo "<tr>";
echo "<th>Datum</th>";
echo "<th> Vakantie uren</th>";
echo "<th> Vakantie uren opgennomen </th>";
echo "<th> Nieuw aantal vakantie uren</th>";
echo "</tr>";
if ($resultCheck > 0) {
while ($row = mysqli_fetch_assoc($result)) {
if( (!empty($row['datum']) || $row['datum'] == 0)
&& (!empty($row['v']) || $row['v'] == 0)
&& (!empty($row['vo']) || $row['vo'] == 0)
&& (!empty($row['nav']) || $row['nav'] ==0)
) {
echo "<tr>";
echo "<td>".$row['datum']."</td>";
echo "<td>".$row['v']."</td>";
echo "<td>".$row['vo']."</td>";
echo "<td>".$row['nav']."</td>";
echo "</tr>";
}
}
echo "</table>";
}
?>

Answer 2

Well, in PHP, empty is evaluated as false, so your if condition will be false.
If you want to display 0 where the value is empty, you can use the Ternay Operator:
$foo = '';
echo $foo ? $foo : '0'; // 0
Check it out: https://3v4l.org/Beem1.