Replacing mysql_num_fields() for result column counts

mysql_num_fields() counted the number of columns in a result set using PHP's removed MySQL extension. Current PHP provides direct equivalents in PDO and MySQLi.

Historical mysql_num_fields()

<?php
// Historical only.
$result = mysql_query('SELECT * FROM student');
$fields = mysql_num_fields($result);
echo $fields;
?>

PDO columnCount()

<?php
$stmt = $dbo->query(
    'SELECT id, name, class, mark FROM student'
);
echo $stmt->columnCount();
?>

MySQLi field_count

<?php
$result = $connection->query(
    'SELECT id, name, class, mark FROM student'
);
echo $result->field_count;
?>

The SELECT list controls the count

SELECT name, id
FROM student;

The query above has two result columns even if the underlying table has many more. To count rows rather than columns, use row-count techniques or SQL COUNT().

Related tutorials

Field names · Column metadata · Row counts · COUNT() · SELECT

← All PHP & MySQL topics

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

About the author   Watch on YouTube

Connect: