Error message in PHP when there's no data via MYSQL?

Question

I've got a php file fetching some data from a MYSQL database. This is my code so far:

<?php
    include 'DB.php';
    $connection=mysql_connect(DB_SERVER,DB_USER,PASS);
    $db=mysql_select_db(DB_Name);
    $sql="select * from lookup where id = ".$_GET['id'];
    $res=mysql_query($sql) or die(mysql_error());
    while($row=mysql_fetch_array($res))
        {
        echo $row['message'];
        }
?>

What would I have to add so that if there was no data, there'd be an error message? I'm guessing an If/else statement but I'm not sure how to fit it in with the while syntax.. any help?

php.net/manual/en/function.mysql-num-rows.php is what you want. — andrewsi
– andrewsi, Commented Sep 20, 2012 at 20:13

Marc B · Accepted Answer · 2012-09-20 20:13:24Z

1

$res = mysql_query(...) ...;
if (mysql_num_rows($res) == 0) {
   die("Hey, nothing here!");
}

Beyond that:

a) you're utterly vulnerable to SQL injection attacks. Stop your coding project and learn about them before you go any further.

b) stop using the mysql_*() functions. They're deprecated.

answered Sep 20, 2012 at 20:13

Marc B

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2 Comments

user1686689 Over a year ago

I'll look into the SQL injection article, thank you. And sorry.. could you give me the answer embedded in my current code? Real beginner here.. Thanks!

Marc B Over a year ago

Best way to learn: figure out how to add that code to yours yourself. Because, frankly, this is a very very trivial addition. If you can't figure it out yourself, you definitely won't be up to tackling harder stuff later on.

alanmanderson · Accepted Answer · 2012-09-20 20:14:02Z

0

You can use $count = mysql_num_rows($res); to get the number of rows returend. Then you can use an if statement to display whatever error.

answered Sep 20, 2012 at 20:14

alanmanderson

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Comments

Randy · Accepted Answer · 2012-09-20 20:27:27Z

0

I did it like mentioned above:

$query = "select * from lookup where id = ".$_GET['id'];
$result = mysql_query($query) or die ("Error in query: $query " . mysql_error());
$num_results = mysql_num_rows($result);
if ($num_results == 0){
echo "nothing here</br>";
}
else{
echo "<b> $num_results </b> result(s) match your query</br>";
while($row=mysql_fetch_array($res))
    {
    echo $row['message'];
    }

You can of course leave the "echo $num_results..." out, but there you can give the number of results, which is sometimes quite useful.

answered Sep 20, 2012 at 20:27

Randy

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