Insert a character (-) if result is empty [duplicate] - php

Question

This question already has answers here:
check if variable empty
(12 answers)
Closed 4 years ago.
I have this following code:
$result = $conn->query($query);
if ($result->num_rows > 0) {
while($row = $result->fetch_assoc())
{
echo "<tr>";
echo "<td>" . preg_replace('/[^0-9]+/','',$row['total']) . "</td>";
echo "</tr>";
}
What I try to do is if the output is empty, then insert (-) character. Only if there is no value output.
I tried this:
$result = $conn->query($query);
if ($result->num_rows > 0) {
$total = $total ?? "" ?: "-";
while($row = $result->fetch_assoc())
{
echo "<tr>";
echo "<td>" . $total . "</td>";
echo "</tr>";
}
this replaces all outputs with (-).
How can I achieve this? please. thank you for your help!
Note that if the result of preg_replace('/[^0-9]+/','',$row['total']) is empty, then it should insert (-) character.
The inputs are like this:
100.
80.
70.
etc
Expected output would be something like this:
Total
100
90
-
80
70
-
10

Answer 1

You can check total value and replace it if it is empty. For example:
while($row = $result->fetch_assoc()) {
$total = empty($row['total']) ? '-' : preg_replace('/[^0-9]+/','',$row['total']);
echo "<tr>";
echo "<td>" . $total . "</td>";
echo "</tr>";
}

Answer 2

you can also use case statement in mysql
SELECT (CASE
WHEN total regexp '^[0-9]+$' THEN total
ELSE '-' END) as total
FROM `tbl_order`
where regexp '^[0-9]+$' matches whether variable total is numeric or not
by using case we check if total is numeric then print total otherwise -