WordPress MYSQL Error

Can someone help me fix the error below?

ERROR

[Fri Mar 04 23:37:59.682275 2016] [:error] [pid 9392] [client
222.127.94.8:45468] WordPress database error You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server
version for the right syntax to use near ” at line 10 for query
SELECT DISTINCT ID, post_title, post_password, comment_ID,n
comment_post_ID, comment_author, comment_author_email,
comment_date_gmt, comment_approved,n
comment_type,comment_author_url,n SUBSTRING(comment_content,1,110) AS
com_excerptn FROM wp_commentsn LEFT OUTER JOIN wp_posts ON
(wp_comments.comment_post_ID =n wp_posts.ID)n WHERE comment_approved
= ‘1’ AND comment_type = ” ANDn post_password = ”n ORDER BY comment_date_gmt DESC LIMIT made by require(‘wp-blog-header.php’),
require_once(‘wp-includes/template-loader.php’),
include(‘/themes/theme/404.php’), dynamic_sidebar,
call_user_func_array, WP_Widget->display_callback, Comments->widget,
referer:

Code in Theme:

$sql = "SELECT DISTINCT ID, post_title, post_password, comment_ID,
comment_post_ID, comment_author, comment_author_email, comment_date_gmt, comment_approved,
comment_type,comment_author_url,
SUBSTRING(comment_content,1,100) AS com_excerpt
FROM $wpdb->comments
LEFT OUTER JOIN $wpdb->posts ON ($wpdb->comments.comment_post_ID =
$wpdb->posts.ID)
WHERE comment_approved = '1' AND comment_type = '' AND
post_password = ''
ORDER BY comment_date_gmt DESC LIMIT ".$comment_posts;

$comments = $wpdb->get_results($sql);
$output = $pre_HTML;

foreach ($comments as $comment) {

What do i need to replace in the CODE above to fix the error?

Thank you in advance