How do I retrieve the max value of a column in SQL using PHP?
Table name is pages
.
The code I have written into a function is:
function max_from_page($column) {
global $db;
$sql = "SELECT MAX('" . $column . "')";
$sql.= "FROM pages";
$result = mysqli_query($db, $sql);
return $result;
}
UPDATE 1: I added an alias:
function max_from_page($column) {
global $db;
$sql = "SELECT MAX(" . $column . ") AS maxsub";
$sql.= "FROM pages";
$result = mysqli_query($db, $sql);
return $result;
}
Then a var dump echo'ed bool(false)
UPDATE 2: So after adding a space before FROM
The var dump gives me this:
object(mysqli_result)#2 (5) { ["current_field"]=> int(0) ["field_count"]=> int(1) ["lengths"]=> NULL ["num_rows"]=> int(1) ["type"]=> int(0) }
The max value I am expecting returned is 3
. The above code executes absolutely fine on MYSQL command line.
You're using $result = mysqli_query($db, $sql);
to return the result. mysqli_query
does return an mysqli-object
(if query has been sucsseful) but wont return the actual result of the query.
You should use
$result = mysqli_fetch_assoc($result);
And then you would have $result['maxsub']
as the value you're looking for.
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