Relationship of conditional query plus sort and index in MySQL

With a friend, a good company supervisor. When communicating with the index in MySQL in conditional query and sort

Mysql> Explain select * from article where title= ' Hope PV Enterprise survived 2 months ' O

Rder by ID desc\\\\\\\\g

1. Row ***************************

Id:1

Select_type:simple

Table:article

Type:index

Possible_keys:null

Key:primary

Key_len:4

Ref:null

rows:567

Extra:using where

1 row in Set (0.00 sec)

Mysql> SELECT * from article where title= ' Hope PV Enterprise survived 2 months ';

+----+-------------+---------+--------+-----------------------------+----------+

-----------+-------+-------------+---------+---------+--------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------+--------+--

---------+--------+------------+------------+

| ID | category_id | user_id | app_id | Title | Subtitle |

Professor | Money | Cooperation | Project | Address | Discription

| SOURCE | R

Ecommend | Status | CTime | Mtime |

+----+-------------+---------+--------+-----------------------------+----------+

-----------+-------+-------------+---------+---------+--------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------+--------+--

---------+--------+------------+------------+

|           10 |       2 |      4 | 0 |          Hope PV Enterprise survived 2 months | |

|             0 |         |         | |        Hope the enterprise survived two months. | |

1 | 0 | 1371524848 | 1371525226 |

+----+-------------+---------+--------+-----------------------------+----------+

-----------+-------+-------------+---------+---------+--------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------+--------+--

---------+--------+------------+------------+

1 row in Set (0.00 sec)

Mysql> Explain select * from article where title= ' Hope PV Enterprise survived 2 months ';

+----+-------------+---------+------+---------------+------+---------+------+---

---+-------------+

| ID | Select_type | Table | Type | Possible_keys | Key | Key_len | Ref | Ro

WS | Extra |

+----+-------------+---------+------+---------------+------+---------+------+---

---+-------------+

| 1 | Simple | Article | All | NULL | NULL | NULL |  NULL | 5

67 | Using where |

+----+-------------+---------+------+---------------+------+---------+------+---

---+-------------+

1 row in Set (0.00 sec)

Developers in the big department would think that the first query would not use the index

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Relationship of conditional query plus sort and index in MySQL