I have a table structure like
comment_id primary key
comment_content
comment_author
comment_author_url
When I fire query like
explain SELECT * FROM comments ORDER BY comment_id
It outputs the results as
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE comments ALL NULL NULL NULL NULL 22563 Using filesort
Why is not able to find the index that I have defined as Primary Key?