WordPress | WP_Query(‘s=a’) returns nothing

I have the following code:

$data = new WP_Query('s=a');

and the print_r returns the following data:

WP_Query Object
(
    [query_vars] => Array
        (
            [s] => a
            [error] => 
            [m] => 0
            [p] => 0
            [post_parent] => 
            [subpost] => 
            [subpost_id] => 
            [attachment] => 
            [attachment_id] => 0
            [name] => 
            [static] => 
            [pagename] => 
            [page_id] => 0
            [second] => 
            [minute] => 
            [hour] => 
            [day] => 0
            [monthnum] => 0
            [year] => 0
            [w] => 0
            [category_name] => 
            [tag] => 
            [cat] => 
            [tag_id] => 
            [author_name] => 
            [feed] => 
            [tb] => 
            [paged] => 0
            [comments_popup] => 
            [meta_key] => 
            [meta_value] => 
            [preview] => 
            [sentence] => 
            [fields] => 
            [menu_order] => 
            [category__in] => Array
                (
                )

            [category__not_in] => Array
                (
                )

            [category__and] => Array
                (
                )

            [post__in] => Array
                (
                )

            [post__not_in] => Array
                (
                )

            [tag__in] => Array
                (
                )

            [tag__not_in] => Array
                (
                )

            [tag__and] => Array
                (
                )

            [tag_slug__in] => Array
                (
                )

            [tag_slug__and] => Array
                (
                )

            [ignore_sticky_posts] => 
            [suppress_filters] => 
            [cache_results] => 1
            [update_post_term_cache] => 1
            [update_post_meta_cache] => 1
            [post_type] => any
            [posts_per_page] => 10
            [nopaging] => 
            [comments_per_page] => 50
            [no_found_rows] => 
            [search_terms] => Array
                (
                    [0] => a
                )

            [order] => DESC
        )

    [tax_query] => WP_Tax_Query Object
        (
            [queries] => Array
                (
                )

            [relation] => AND
        )

    [meta_query] => WP_Meta_Query Object
        (
            [queries] => Array
                (
                )

            [relation] => 
        )

    [post_count] => 0
    [current_post] => -1
    [in_the_loop] => 
    [comment_count] => 0
    [current_comment] => -1
    [found_posts] => 0
    [max_num_pages] => 0
    [max_num_comment_pages] => 0
    [is_single] => 
    [is_preview] => 
    [is_page] => 
    [is_archive] => 
    [is_date] => 
    [is_year] => 
    [is_month] => 
    [is_day] => 
    [is_time] => 
    [is_author] => 
    [is_category] => 
    [is_tag] => 
    [is_tax] => 
    [is_search] => 1
    [is_feed] => 
    [is_comment_feed] => 
    [is_trackback] => 
    [is_home] => 
    [is_404] => 
    [is_comments_popup] => 
    [is_paged] => 
    [is_admin] => 
    [is_attachment] => 
    [is_singular] => 
    [is_robots] => 
    [is_posts_page] => 
    [is_post_type_archive] => 
    [query_vars_hash] => 1015947de489d0153582586bded7c016
    [query_vars_changed] => 
    [thumbnails_cached] => 
    [query] => Array
        (
            [s] => a
        )

    [request] => SELECT * FROM wp_posts WHERE 1=2
    [posts] => Array
        (
        )

)

What is wrong with this query and does not return any data ? Also take a look at the “requer” where it is “SELECT * FROM wp_posts WHERE 1=2”