WordPress at a glance
filter is not described

comment_feed_where filter-hook . WP 2.2.0

Filters the WHERE clause of the comments feed query before sending.

Usage

add_filter( 'comment_feed_where', 'filter_function_name_2767', 10, 2 );
function filter_function_name_2767( $cwhere, $this ){
	// filter...

	return $cwhere;
}
$cwhere(string)
The WHERE clause of the query.
$this(WP_Query)
The WP_Query instance (passed by reference).

Where the hook is called

WP_Query::get_posts()
wp-includes/class-wp-query.php 2436
$cwhere = apply_filters_ref_array( 'comment_feed_where', array( $cwhere, &$this ) );
wp-includes/class-wp-query.php 2858
$cwhere = apply_filters_ref_array( 'comment_feed_where', array( "WHERE comment_post_ID = '{$this->posts[0]->ID}' AND comment_approved = '1'", &$this ) );

Where the hook is used (in WP core)

Does not used.