Reply To: Metabox 4.15.4 (switch)

I have this:

array(
                'name'  => __( 'Show until', TEXTDOMAIN ),
                'id'    => $prefix . 'show_until',
                'type'  => 'datetime',
                'size'  => 20,
                'js_options' => array(
                    'regional'        => 'cz',
                    'appendText'      => '',
                    'dateFormat'      => 'yy-mm-dd',
                    'changeMonth'     => true,
                    'changeYear'      => true,
                    'showButtonPanel' => false
                )
            ),

What i have to do, if i would like default (empty?) record in DB (like 0 in switch)? The reason is, that i must query posts with conditional test EXISTS on this field - this is performance issue on larges sites..