Re: except (was: Keys with duplicates should be simple

On Sun, Feb 2, 2014 at 9:04 PM, Michael Kay <mike@xxxxxxxxxxxx> wrote:
>
>>
>> So while I agree with you on the whole, I also make an exception for
>> 'except'. It just isn't that bad. Indeed, there is an entire
>> profession of people (I think they're called 'mathematicians') who
>> consider such verbal stunt work to be just a day at the office.
>>
>
> Indeed, I'm a little curious as to why "except" causes problems. I think we chose "except" rather than "difference" because "except" would be more meaningful to non-mathematicians.
>

because it doesn't meet neither the natural language expectation and
it doesn't meet the mathematicians expectation. I would also quibble
with the label of mathematician since

a) as stated back then it's only high school maths
b) you are already on the "mathematical" using intersect and union so
one would not expect a departure for difference

I think I observed at the time as well that it may have been copied
from SQL but I don't think the SQL except interprets the same way (i.e
I think it is more in line with the natural language expectation).