Re: Fixing row comparison semantics

Tom Lane wrote:
> Christopher Kings-Lynne <chriskl(at)familyhealth(dot)com(dot)au> writes:
> > Can someone explain to me how:
> > (a, b) < (1, 2)
> > is different to
> > a < 1 and b < 2
>
> Right at the moment our code interprets it that way, but this behavior
> is wrong per spec. It should be an ordered column-by-column comparison,
> so that the equivalent simple expression is
>
> (a < 1) OR (a = 1 AND b < 2)

TODO updated:

* %Make row-wise comparisons work per SQL spec

Right now, '(a, b) < (1, 2)' is processed as 'a < 1 and b < 2', but
the SQL standard requires it to be processed as a column-by-column
comparison, so the proper comparison is '(a < 1) OR (a = 1 AND b < 2)'

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