This is the select function, from my php_database function (https://github.com/brazucaz/php_database/blob/master/src/class.database.php)

mysqli.select.php

<?php
/**
* Get content from the database
*
* @param $fields an array with what columns to pull
* @param $table which table to query
*
* @return $content with the table content
* @return $message with either an error or success message
*/
public function select( array $fields, string $table, $extra = '' )
{
    $message = array();

    if( !is_array( $fields ) )
    {
        $message = array(
            'is_error' => 'warning',
            'message' => 'Invalid type given for $fields'
        );
        return $message;
        exit();
    }

    foreach($fields as $value)
    {
        $val[] = $value;
    }

    $rows = implode(', ', $val);

    $sql = "SELECT " . $rows . " FROM " . $table . " " . $extra;

    if ($result = $this->_connection->query( $sql ))
    {
        if ($result->num_rows > 0)
        {
            try
            {
                while ($row = $result->fetch_assoc())
                {
                    $content[] = $row;
                }
                return $content;
            }
            catch (Exception $e)
            {
                trigger_error("Error: " , $e->getMessages());
                exit();
            }
        }
        else
        {
            $message = array(
                'is_error' => 'warning',
                'message' => 'There are no records in the `' . $table . '` table.'
            );
            return $message;
            exit();
        }
    }
    else
    {
        $message = array(
            'is_error' => 'danger',
            'message' => 'Query Error, please revise the information.'
        );
        return $message;
        exit();
    }
}