* of top-level $column. Accepts 'post_date', 'post_date_gmt',
* 'post_modified', 'post_modified_gmt', 'comment_date', 'comment_date_gmt'.
* @type string $compare Optional. The comparison operator. Default '='. Accepts '=', '!=',
* of top-level $column. Accepts 'post_date', 'post_date_gmt',
* 'post_modified', 'post_modified_gmt', 'comment_date', 'comment_date_gmt'.
* @type string $compare Optional. The comparison operator. Default '='. Accepts '=', '!=',