214c214
<     $sqlcat = '';
---
>     $join = '';
216c216,222
<       $sqlcat = " AND post_category = '$current_category' ";
---
>     	$join = " INNER JOIN $wpdb->post2cat ON $wpdb->posts.ID= $wpdb->post2cat.post_id ";
> 	$cat_array = $wpdb->get_col("SELECT category_id FROM $wpdb->post2cat WHERE post_id = $post->ID");
> 	$join .= ' AND (category_id = ' . intval($cat_array[0]);
> 	for ($i = 1; $i < (count($cat_array)); $i++) {
> 		$join .= ' '.$andor.' category_id '.$eq.' '.intval($cat_array[$i]);
> 	}
> 	$join .= ')'; 
228c234
<     return @$wpdb->get_row("SELECT ID, post_title FROM $wpdb->posts WHERE post_date < '$current_post_date' AND post_status = 'publish' $sqlcat $sql_exclude_cats ORDER BY post_date DESC LIMIT 1");
---
>     return @$wpdb->get_row("SELECT ID, post_title FROM $wpdb->posts $join WHERE post_date < '$current_post_date' AND post_status = 'publish' $sql_exclude_cats ORDER BY post_date DESC LIMIT 1");
241c247
<     $sqlcat = '';
---
>     $join = '';
243c249,255
<       $sqlcat = " AND post_category = '$current_category' ";
---
>     	$join = " INNER JOIN $wpdb->post2cat ON $wpdb->posts.ID= $wpdb->post2cat.post_id ";
> 	$cat_array = $wpdb->get_col("SELECT category_id FROM $wpdb->post2cat WHERE post_id = $post->ID");
> 	$join .= ' AND (category_id = ' . intval($cat_array[0]);
> 	for ($i = 1; $i < (count($cat_array)); $i++) {
> 		$join .= ' '.$andor.' category_id '.$eq.' '.intval($cat_array[$i]);
> 	}
> 	$join .= ')'; 
257c269
<     return @$wpdb->get_row("SELECT ID,post_title FROM $wpdb->posts WHERE post_date > '$current_post_date' AND post_date < '$now' AND post_status = 'publish' $sqlcat $sql_exclude_cats AND ID != $post->ID ORDER BY post_date ASC LIMIT 1");
---
>     return @$wpdb->get_row("SELECT ID,post_title FROM $wpdb->posts $join WHERE post_date > '$current_post_date' AND post_date < '$now' AND post_status = 'publish' $sql_exclude_cats AND ID != $post->ID ORDER BY post_date ASC LIMIT 1");
506c518
< ?>
\ No newline at end of file
---
> ?>