MySQL Bugs: #92242: create table with primary key ,allow use index name,but it not real used

Bug #92242	create table with primary key ,allow use index name,but it not real used
Submitted:	30 Aug 2018 9:44	Modified:	30 Aug 2018 11:29
Reporter:	Wei Liu	Email Updates:
Status:	Duplicate	Impact on me:	None
Category:	MySQL Server: Parser	Severity:	S3 (Non-critical)
Version:		OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
mysql> create table x(id int ,PRIMARY KEY  PK_COUPON_ACCESS_201805                (ID));
Query OK, 0 rows affected (0.06 sec)

mysql> show create table x;
+-------+-------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                          |
+-------+-------------------------------------------------------------------------------------------------------+
| x     | CREATE TABLE `x` (
  `id` int(11) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+-------+-------------------------------------------------------------------------------------------------------+
1 row in set (0.03 sec)

mysql> show index from x\G
*************************** 1. row ***************************
        Table: x
   Non_unique: 0
     Key_name: PRIMARY
 Seq_in_index: 1
  Column_name: id
    Collation: A
  Cardinality: 0
     Sub_part: NULL
       Packed: NULL
         Null:
   Index_type: BTREE
      Comment:
Index_comment:
1 row in set (0.03 sec)

How to repeat:
as description

mysql> create table x(id int ,PRIMARY KEY  PK_COUPON_ACCESS_201805                (ID));
Query OK, 0 rows affected (0.06 sec)

mysql> show create table x;
+-------+-------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                          |
+-------+-------------------------------------------------------------------------------------------------------+
| x     | CREATE TABLE `x` (
  `id` int(11) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+-------+-------------------------------------------------------------------------------------------------------+
1 row in set (0.03 sec)

mysql> show index from x\G
*************************** 1. row ***************************
        Table: x
   Non_unique: 0
     Key_name: PRIMARY
 Seq_in_index: 1
  Column_name: id
    Collation: A
  Cardinality: 0
     Sub_part: NULL
       Packed: NULL
         Null:
   Index_type: BTREE
      Comment:
Index_comment:
1 row in set (0.03 sec)

Suggested fix:
make this sql syntax failed for use index name on a primary key

or

use the name as key name

Hello Wei Liu,

Thank you for the report.
Imho key name is ignored here, and this is most likely duplicate of our Shane's Bug #47771 where such "parser" issues are tracked.

Also, please see Bug #1956

Thanks,
Umesh