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

Getting Single Column Values with MySQLi

When retrieving data from a MySQL database using MySQLi, it's sometimes necessary to extract values from a specific column into a one-dimensional array. However, developers often encounter an issue where the result is a multidimensional array.

To address this issue, it's recommended to use the fetch_assoc() method instead of fetch_row(). This method returns an associative array where the column names are used as keys, providing a direct and convenient way to access individual column values:

<code class="php"><?php
$conn = new mysqli("localhost", "username", "password", "database");

if (!$conn) {
  printf("Could not connect to database: %s\n", $mysqli->error);
  exit;
}

$query = "SELECT DISTINCT `EmailAddress` FROM `Emails` WHERE `JobID` = 1";
$result = $conn->query($query);

if (!$result) {
  printf("Query failed: %s\n", $mysqli->error);
  exit;
}

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

$result->close();
$conn->close();

var_dump($rows); // Output: array(2) { [0] => "username@example.com", [1] => "username2@example.com" }

?></code>

By using fetch_assoc(), the result will be a one-dimensional array containing only the values from the specified column. This simplifies the data retrieval process and ensures the desired output.

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