What is the purpose of using count(distinct) in PHP and how does it work?

Using count(distinct) in PHP allows you to count the number of unique values in a column of a database table. This can be useful when you want to get a count of distinct values rather than a count of all values, such as when you want to know how many different users have made purchases. The count(distinct) function works by counting only the unique values in the specified column. 

// Example of using count(distinct) in PHP
$query = "SELECT COUNT(DISTINCT user_id) AS unique_users FROM purchases";
$result = mysqli_query($connection, $query);
$row = mysqli_fetch_assoc($result);
echo "Number of unique users: " . $row['unique_users'];

Keywords

count distinct PHP query aggregation

Related Questions