The repeater field holds an integer representing the number of rows. The meta query would look something like this
$meta_query = array(
'relation' => 'AND',
array(
'key' => 'your-repeater-field-name',
'compare' => 'EXISTS'
),
array(
'key' => 'your-repeater-field-name',
'value' => 0,
'type' => 'NUMERIC'
'compare' => '>'
),
)
the meta_key exists and it’s value is > 0