BUG #1106: Big5 String equal doesn't work

The following bug has been logged online:

Bug reference: 1106
Logged by: Jer-Min Tsai

Email address: tjm(at)fhl(dot)net

PostgreSQL version: 7.4

Operating system: Linux Fedora Core 1

Description: Big5 String equal doesn't work

Details:

DataBase Version 7.4 ,7.2
DataBase Encoding EUC_TW
client encoding Big5

SQL as below:

create table main(
name character(10),
gender character(1),
birthday timestamp,
tel character(16),
fax character(16),
mobil character(16),
email character(60),
address character(100)
);

insert into main values
('','','1986/02/13','07-1234567','06-03213213','09311234567'
,'tjm(at)vexp(dot)idv(dot)tw','');
insert into main values
('','','1943/05/15','06-1234567','02-03213213','09181234567'
,'ban(at)gov(dot)tw','');
insert into main values
('','','1923/06/16','02-7654321','02-43210321','09601234567'
,'jan(at)kmt(dot)org(dot)tw','');
insert into main values
('','','1928/02/18','04-1234567','04-03213213','09601234567'
,'yui(at)green(dot)org(dot)tw','');
insert into main values
('','','1943/02/13','06-1234567','02-03213213','09181234567'
,'tjm(at)vexp(dot)idv(dot)tw','');
insert into main values
('','','1935/12/05','02-1234567','02-03213213','09184321231'
,'tjm(at)vexp(dot)idv(dot)tw','');

select * from main where gender='';

It can not show only gender=''.
I tried Like '' is ok. = ASCII String is ok.