ACF 繰り返しフィールド

<?php if( have_rows( 'add_banner', 4950 ) ): ?>
<?php while( have_rows( 'add_banner', 4950 ) ): the_row(); ?>
<?php
$img = get_sub_field( 'banner', 4950 );
$url = $img['sizes']['medium'];
$alt = $img['alt'];
?>
<div class="side__banner--wrapper--img">
<a href="<?php the_sub_field('link', 4950); ?>" target="_blank" rel="noopener" onclick="ga('send', 'event', 'sidebar','click', '<?php echo $alt ?>', 1);"><img src="<?php echo $url ?>" alt="<?php echo $alt ?>"></a>
</div>
<?php endwhile; ?>
<?php endif; ?>