I had similar.
If you look at the below:
$rows = $wpdb->get_results($wpdb->prepare( " SELECT * FROM wp_postmeta WHERE meta_key LIKE %s AND meta_value LIKE %s GROUP BY meta_value ASC", 'dates_%_available_dates', ''.$year.''.$month.'%', "" ));
You can see that dates_%_available_dates is the repeater field as it went:
Using the % allows you to be more dynamic, as you can search on all with the LIKE statement
It may help you with your code. I most certainly think rewriting your query to something like my example or the one in the link will help though
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