This is Warren Kwok's Internet note pad, electronic diary, online rubbish journal, whatever you might name it ! It is an archive of my random thoughts in a chronological order. I am not good at reporting boring things and change them to lively. If you find this blog boring, sorry that it is your problem.
an unknown value, and strictly speaking NULL is never equal to NULL. To say NULL means “does not exist”
might not be lexically correct. Confusing about what I said about, then put me