但是默认不是开启的。若要开启此功能，可以在Linux中
vi /etc/my.cnf
[mysql]
#no-auto-rehash
auto-rehash #添加auto-rehash
即将[mysql]中的no-auto-rehash改为auto-rehash
再次登陆MySQL就可以自动补全了。
如果你想尝试在Windows中做同样尝试，会发现不会成功。
原因在下面的英文中有解释：
It ought to work this way:
C:> mysql --auto-rehash
Or configure your my.cnf:
[mysql]
auto-rehash
edit: My apologies. I have found some references that the tab-completion feature in mysql client works only on UNIX/Linux. It does not work on Windows.
update: The reason for this is mentioned briefly in MySQL bug #4731:
[31 Jul 2004 12:47] Sergei Golubchik
I just downloaded 4.0.15 - command completion in mysql.exe is
NOT working, as expected. It was never working in mysql.exe because
we were not able to make readline to compile with VC++.
mysqlc.exe is a cygwin build, and it is linked with
readline.
Explanation: GNU readline is a standard open-source library for handling user input. The MySQL team uses the readline library, but they are not its author. From the above comment, I understand that they were unsuccessful in compiling the readline library on Windows with Microsoft Visual C++, the tool they use to build the MySQL product. Some open-source projects have not been made fully compatible with the Microsoft Windows environment.
At one time in the past, the MySQL
product provided an alternative client they called mysqlc.exe,
which they compiled with the cygwin toolset on Windows, but they don't provide
this anymore. The cygwin toolset includes the readline library, so
it was possible to compile the mysqlc.exe client with support for
tab-completion.
So in theory, if you are really intrepid, you could download the
cygwin toolset including the readline library, then download the
MySQL source code and build it using cygwin. Then you should have a
mysql client program that can perform tab-completion. But this
sounds like a lot of work even for someone who is familiar with
building MySQL from source.
这是MySQL Windows版本的一个Bug :-)