Syntax-errored ALTER TABLE is exported

[yoku0825]

Description

• phpMyAdmin exports incorrect (syntax-errored) ALTER TABLE when the table has comment of INDEX.
• Environment which I can reproduce,
  • phpMyAdmin 4.5.4.1
  • MySQL 5.6.28
  • PHP 5.6.18

How to repeat

• Create table which has comment of INDEX(This step has no difference whether using CLI or phpMyAdmin)

CREATE DATABASE d1;
CREATE TABLE d1.t1 (num int COMMENT 'This is comment of Columu', KEY (num) COMMENT 'This is comment of Index') COMMENT= 'This is comment of Table';

• Click "Export" tab and choise "Quick" as Export method, "SQL" as Format. (Nothing have to do from default)
• Execute statements in dump file and you'd got error.

mysql> CREATE TABLE `t1` (
    ->   `num` int(11) DEFAULT NULL
    -> ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='This is comment of Table';
Query OK, 0 rows affected (0.01 sec)

mysql> ALTER TABLE `t1`
    ->   ADD KEY `num` (`num`) COMMENT='This is comment of Index';
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '='This is comment of Index'' at line 2

• And you can find comment of Column disappeared from dump file.

Suggested fix

• Remove incorrect "=" from exported ALTER TABLE statement.

mysql> ALTER TABLE t1 Comment = 'This is correct comment of table'; -- "COMMENT" with "=" for Comment of Table
mysql> ALTER TABLE t1 Comment 'This is correct comment of table';   -- "COMMENT" without "=" for Comment of Table
mysql> ALTER TABLE t1 ADD KEY (num) Comment = 'This is wrong'; -- "COMMENT" with "=" for Comment of Index
mysql> ALTER TABLE t1 ADD KEY (num) Comment 'This is correct comment of Index'; -- "COMMENT" without "=" for Comment of Index

Whole SQL Dump file is following

-- phpMyAdmin SQL Dump
-- version 4.5.4.1
-- http://www.phpmyadmin.net
--
-- Host: 172.17.1.211
-- Generation Time: Feb 16, 2016 at 08:10 AM
-- Server version: 5.6.28
-- PHP Version: 5.6.18

SET SQL_MODE = "NO_AUTO_VALUE_ON_ZERO";
SET time_zone = "+00:00";


/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8mb4 */;

--
-- Database: `d1`
--
CREATE DATABASE IF NOT EXISTS `d1` DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;
USE `d1`;

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

--
-- Table structure for table `t1`
--

CREATE TABLE `t1` (
  `num` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='This is comment of Table';

--
-- Indexes for dumped tables
--

--
-- Indexes for table `t1`
--
ALTER TABLE `t1`
  ADD KEY `num` (`num`) COMMENT='This is comment of Index';

/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;