Finally I have solved the problem of inputting Chinese characters into a MySQL database.

I am using Apache 1.3, PHP4 and MySql 3.23 on Windows 98.
My solution is as follows:

1.Use another MySQL client to input Chinese characters via the browser.
2.The client I chose is phpMyAdmin, written by Tobias Ratschiller, available at http://www.phpwizard.net
3.After downloading the phpMyAdmin program, unzip it and copy the phpMyAdmin folder to the directory of PHP. (for the sake of grouping files only, since the program is written in PHP)
4.Edit the http.conf file of Apache in the Apache/conf subdirectory. You need to add only one line in the Alias section. For your reference I am quoting all the lines necessary for both PHP4 and PhpMyAdmin:

Alias /data/ "C:/php/data/" //(document root of .php files except those of phpMyAdmin)
Alias /mysql/ "C:/php/phpMyAdmin/"
ScriptAlias /php/ "C:/php/"
AddType application/x-httpd-php .php .inc .phtml
Action application/x-httpd-php "/php/php.exe"

5.In the C:/windows/php.ini file leave the following 2 lines empty:
[Paths and Directories]
include_path=
doc_root=

6.Connect to Internet, start Apache, start MySQL, then from your browser type "localhost/data/...php" all files with php extension in the c:/php/data directory and its sub-directories should be seen.

7. Type "localhost/mysql/index.php" the phpMyAdmin client program should come up. You can then view, add, edit and delete your MySQL database via the web in any language.

8. If you type localhost/...php, your .php file in C:/php directory would be seen.

Thanks to all those friends helping me solve the problem.
What a friendly and helyful community!