| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | "Pavel Stehule" <pavel(dot)stehule(at)hotmail(dot)com> |
| Cc: | pgman(at)candle(dot)pha(dot)pa(dot)us, chriskl(at)familyhealth(dot)com(dot)au, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Fixing row comparison semantics |
| Date: | 2005-12-26 16:07:48 |
| Message-ID: | 9884.1135613268@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
"Pavel Stehule" <pavel(dot)stehule(at)hotmail(dot)com> writes:
>> 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)'
> Can we save current behave (with small modification) with other operator,
> like <*
Huh? The only "current behavior" with other operators is failure:
regression=# select (1,1) <* (1,2);
ERROR: operator <* is not supported for row expressions
In any case, you can get the equivalent of the current behavior by
writing out
1 <* 1 AND 1 <* 2
so I don't see any strong need to support non-SQL-spec behaviors here.
regards, tom lane
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