Question

i have a select query. another short if-form checks if this select query returns something or not.

so i have:

$query = "SELECT `a` FROM `b` WHERE c='$c'";
$test = ($query = mysql_query($query)) ? $mysql_num_rows($query) : 0;

so i would like to convert into mysqli but the following code seems to be wrong ($db = mysqli):

$query = "SELECT `a` FROM `b` WHERE c='$c'";
$test = ($query = $db->query($query)) ? $db->num_rows($query) : 0;

when using:

$test = ($query = mysqli_query($query)) ? mysqli_num_rows($query) : 0;

it will echo the error message:

Warning: mysqli_query() expects at least 2 parameters, 1 given...

so if there is someone who would be that friendly and could give me an advise to solve this i really would appreciate. thanks a lot.

Answer 1

mysqli in procedural mode doesn’t default to using the last-established connection like the mysql library does. You have to explicitly include the connection each time:

$test = ($query = mysqli_query($conn, $query)) ? mysqli_num_rows($query) : 0;
                               ^^^^^^

As well, for num_rows, it’s mysqli_stmt_num_rows($result)