How to Retrieve Single Column Values as a One-Dimensional Array with MySQLi?

Retrieving Single Column Values with MySQLi

It can be challenging to retrieve data from a MySQL database and store it as a one-dimensional array. By default, MySQLi returns multidimensional arrays, as seen in the provided code snippet:

$query = "SELECT DISTINCT `EmailAddress` FROM `Emails` WHERE `JobID` = 1";
$result = $conn->query($query);
while ($row = $result->fetch_row()) {
    $rows[] = $row;
}

This code returns a multidimensional array with each row represented as a separate element. However, the goal is to obtain a one-dimensional array of email addresses.

Solution: Using fetch_assoc()

To rectify this issue, use fetch_assoc() instead of fetch_row(). fetch_assoc() retrieves the row as an associative array, where the column names serve as keys and the values are stored as elements. Here's the modified code:

while ($row = $result->fetch_assoc()) {
    $rows[] = $row['EmailAddress'];
}

By switching to fetch_assoc(), the code successfully stores the email addresses as a one-dimensional array, with each email address stored in its own element:

<code class="php">array(2) {
    [0] => "[email protected]"
    [1] => "[email protected]"
}</code>

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