WordPress at a glance
filter is not described

posts_distinct filter-hook . WP 2.1.0

Filters the DISTINCT clause of the query.

Usage

add_filter( 'posts_distinct', 'filter_function_name_1567', 10, 2 );
function filter_function_name_1567( $distinct, $this ){
	// filter...

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

Where the hook is called

WP_Query::get_posts()
posts_distinct
wp-includes/class-wp-query.php 2549
$distinct = apply_filters_ref_array( 'posts_distinct', array( $distinct, &$this ) );

Where the hook is used (in WP core)

Does not used.