On Sun, Sep 11, 2005 at 03:03:57AM -0400, Tom Lane wrote: > Michael Fuhr <[EMAIL PROTECTED]> 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 examples: http://philip.greenspun.com/sql/dates 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; ADD_MONTHS ---------- 2003-06-30 -- 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'; ?column? --------------------- 2005-09-01 00:00:00 (1 row) test=> select date '2005-08-01' + interval '1' month; ?column? --------------------- 2005-08-01 00:00:00 (1 row) test=> select interval '1' month; interval ---------- 00:00:00 (1 row) What's the parser doing here? -- Michael Fuhr ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org
