wordpress theme customizer dropdown

Question

I am trying to create a select box/dropdown menu in the Wordpress theme customization area where the options are to be extracted from a column called "alias" in a table named "wp_revslider_sliders" from my Wordpress DB.

I have already created the section, and the basic setting and control for the drop down menu (see Fig. 1 below), but being a novice in this area, I can't figure out how to query the Wordpress DB, extract the results from the "Alias" column of my "wp_revslider_sliders" table and insert them output in to the "choices array" below

Fig. 1

$wp_customize->add_control(
    'select_revslider',
array(
    'type' => 'select',
    'label' => 'Please Select a Slider:',
    'section' => 'example_section_one',
    'choices' => array(
        'wordpress' => 'WordPress',
     ),
)
);

Fig. 2

function example_customizer( $wp_customize ) {

$wp_customize->add_section(
    'example_section_one',
    array(
        'title' => 'Example Settings',
        'description' => 'This is a settings section.',
        'priority' => 35,
    )
);

$wp_customize->add_setting(
    'select_revslider',
array(
    'default' => 'wordpress',
)
);


$wp_customize->add_control(
    'select_revslider',
array(
    'type' => 'select',
    'label' => 'Please Select a Slider:',
    'section' => 'example_section_one',
    'choices' => array(
        'wordpress' => 'WordPress',
     ),
)
);

Answer 1

Within your function.php file crate function like this:

function alias_from_wp_revslider_sliders() {

   $sql = "SELECT aliasname FROM wp_revslider_sliders";
   $result = $conn->query($sql);

   $alias_list = array();

      foreach($alias_list as $alias) {
         $alias_list[$alias->aliasname] = $alias->aliasname;
      }

   return  $alias_list;

}

and than when you add the control instead of choices call the function we created inside functions.php

$wp_customize->add_control(
    'select_revslider',
array(
    'type' => 'select',
    'label' => 'Please Select a Slider:',
    'section' => 'example_section_one',
    'choices' => function alias_from_wp_revslider_sliders(),
)