php - Display single column value of mysqli query

Question

How can I get a single column value from mysqli? The result should be single row with only one column.

This is what I have tried:

$query = "SELECT MAX(`userid`) FROM `user`";
$rlt = mysqli_query($this->db, $query);
echo $rlt['userid'];

Answer 1

You are not fetching the row after executing the query:

$query = "SELECT MAX(`userid`) FROM `user'";
$rlt = mysqli_query($this->db,$query);
$row = mysqli_fetch_row($this->db, $rlt);
echo $row[0];

The alternative would be to use an alias for the computed field and use fetch_assoc:

$query = "SELECT MAX(`userid`) as `maxid` FROM `user'";
$rlt = mysqli_query($this->db,$query);
$row = mysqli_fetch_assoc($this->db, $rlt);
echo $row['maxid'];