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Re: BUG #1871: operations with data types

From: Michael Fuhr <mike(at)fuhr(dot)org>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: anris(at)polynet(dot)lviv(dot)ua, pgsql-bugs(at)postgresql(dot)org
Subject: Re: BUG #1871: operations with data types
Date: 2005-09-13 13:10:16
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-bugs
On Sun, Sep 11, 2005 at 03:03:57AM -0400, Tom Lane wrote:
> Michael Fuhr <mike(at)fuhr(dot)org> writes:
> > What do other DBMSs do?
> This is a fair question.  Given that the SQL committee hasn't provided
> any useful leadership, what are other groups doing?

I don't have access to an Oracle system, but the following page has

It looks like Oracle has "old" and "new" (version 9 and later?)
ways of doing the query and they give different results:

  -- old 
  select add_months(to_date('2003-07-31','YYYY-MM-DD'),-1) from dual;
  -- new
  select to_timestamp('2003-07-31','YYYY-MM-DD') - interval '1' month from dual;
  ERROR at line 1:
  ORA-01839: date not valid for month specified

I just noticed something in PostgreSQL that might be considered
surprising (although I do see "Add ISO INTERVAL handling" in the
TODO list):

  test=> select date '2005-08-01' + interval '1 month';
   2005-09-01 00:00:00
  (1 row)
  test=> select date '2005-08-01' + interval '1' month;
   2005-08-01 00:00:00
  (1 row)
  test=> select interval '1' month;
  (1 row)

What's the parser doing here?

Michael Fuhr

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Subject: Re: BUG #1871: operations with data types
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Subject: BUG #1879: ODBC Connection Dies

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