I'm reading [this article](http://www.ferdychristant.com/blog//articles/DOMM-7QJPM7) and I'm trying to understand this SQL statement but I am still somewhat new to SQL. 

I'm not sure what comment and c refer to.  

I think one of them is the table name but I am not sure of the other. Also, apparently there is a subquery within it which I have not had any experience with:

```
  SELECT c.id, c.user_id, c.body, c.deep, c.lineage, c.parent_id,
         (SELECT COUNT(*) 
            FROM comment 
           WHERE comment.lineage LIKE (CONCAT(c.lineage,'%')) 
             AND comment.lineage != c.lineage) AS replies
    FROM comment as c
ORDER BY c.lineage

```