[H-GEN] Mysql & bitwise xor

[Raymond Smith]

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Greg Black said:
> On 2003-11-18, Raymond Smith wrote:
>> Greg Black said:
>> > On 2003-11-17, Paul Clarke wrote:
>> >> So, the next question is what is the logic needed to do an xor
>> >> using only &, |, and ~ (and, or, and not)?
>> >
>> > Have you tried substituting X | ~Y for X ^ Y?
>>
>> Should that not be '(X & ~Y) | (~X & Y)' or '~((X&Y) | (~X&~Y))'?
>
> It was a pedagogical answer, not a solution on a plate.

I see.

> Somehow, I thought I had conveyed all of the above in my one
> line response :-)

I missed it: I was left with the incredible notion that you did
not understand Boolean Algebra. I therefore fell back on the
credible notion that I had gone mad and could no longer understood
Boolean Algebra :-)

> And, by intent, I have still not stated just what is the answer
> to the original question.

I'm not a great fan of this style of teaching. With it, one walks
a fine line between being an enigmatic master, and being a means of
transporting an enigmatic master :-)

To the original poster: if you have 'and', 'or', and 'not' you
can usually do everything you need. A quick search on Google for
'intro boolean logic' should bring up useful starting resources.
When starting out, Truth Tables are your friend.

Cheers,

Raymond
-- 
raymond at humbug.org.au



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