Get wall_post and profile data for several users
Here is your original query

SELECT DISTINCT
    default_profiles.*,default_wall_posts.*,
    UNIX_TIMESTAMP( ) - default_wall_posts.date_created AS pass_time
FROM
    (default_wall_posts)
    LEFT JOIN default_profiles
    ON (default_profiles.user_id = default_wall_posts.userid) 
    AND (default_wall_posts.userid = 2 OR default_wall_posts.userid = 3)
WHERE
    default_wall_posts.userid = 1 AND
    (
        default_wall_posts.userid = 2 AND
        default_wall_posts.userid = 3
    )
ORDER BY
    default_wall_posts.date_created DESC;


The WHERE is impossible to fulfill because default_wall_posts.userid not be 1 and 2 and 3 at the same time.

Try these changes

SELECT DISTINCT
    default_profiles.*,default_wall_posts.*,
    UNIX_TIMESTAMP( ) - default_wall_posts.date_created AS pass_time
FROM
    (default_wall_posts)
    LEFT JOIN default_profiles
    ON (default_profiles.user_id = default_wall_posts.userid) 
WHERE
    default_wall_posts.userid IN (1,2,3)
ORDER BY
    default_wall_posts.date_created DESC;