SHOW CREATE TABLE does not escape the backquotes in the identifiers

[kennytm]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do?

create table `foo``bar` (`id``baz` int);
show create table `foo``bar`;

2. What did you expect to see?

The "Create Table" column should read

CREATE TABLE `foo``bar` (
  `id``baz` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

3. What did you see instead?

The ` in the table and column names aren't escaped, producing the invalid DDL

CREATE TABLE `foo`bar` (
  `id`baz` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

4. What version of TiDB are you using (tidb-server -V or run select tidb_version(); on TiDB)?

Master version.

Release Version: v2.1.0-beta-602-gf3a9745e2
Git Commit Hash: f3a9745e2c42137b069d41a5aa9df9b32195282d
Git Branch: master
UTC Build Time: 2018-11-09 05:14:59
GoVersion: go version go1.11.1 darwin/amd64
Race Enabled: false
TiKV Min Version: 2.1.0-alpha.1-ff3dd160846b7d1aed9079c389fc188f7f5ea13e
Check Table Before Drop: false