Re: Fixing row comparison semantics

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: "Pavel Stehule" <pavel.stehule@hotmail.com>
Cc: pgman@candle.pha.pa.us, chriskl@familyhealth.com.au, pgsql-hackers@postgresql.org
Date: 2005-12-26T16:07:48Z
Lists: pgsql-hackers
"Pavel Stehule" <pavel.stehule@hotmail.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