Dear Ashish,
Thanks for the comment. I found the following things from MySQL 6.0 ::
(1) Inside CREATE TABLE, TIMESTAMP does not have any format. It is treated like
a primitive type (string).
(2) Inside SELECT clause, TIMESTAMP(YYYYMMDDHHMMSS) is called as a routine with
format information for output spec.
=========== MySQL 6.0 function ===============================
TIMESTAMP(expr), TIMESTAMP(expr1,expr2)
With a single argument, this function returns the date or datetime expression
expr as a datetime value. With two arguments, it adds the time expression expr2
to the date or datetime expression expr1 and returns the result as a datetime
value.
mysql> SELECT TIMESTAMP('2003-12-31');
-> '2003-12-31 00:00:00'
mysql> SELECT TIMESTAMP('2003-12-31 12:00:00','12:00:00');
-> '2004-01-01 00:00:00'
===============================================================
As a result, we have to define TIMESTAMP as primitive type as well as a complex
type with format information. I have to upgrade the grammar after further
inspection. I am going to add a basic design document to JIRA.
Please provide suggestions.
Thanks,
Shyam
--- On Mon, 3/9/09, Ashish Thusoo <athu...@facebook.com> wrote:
> From: Ashish Thusoo <athu...@facebook.com>
> Subject: RE: Please check grammar for TIMESTAMP
> To: "hive-dev@hadoop.apache.org" <hive-dev@hadoop.apache.org>
> Date: Monday, March 9, 2009, 2:52 PM
> One immediate issue is that the format string is a lexical
> token, so a string of that format will not conform to the
> grammar at places where a string literal is expected. A
> better approach is to treat the format as a stringliteral
> and then do the format checks at the typecheck and semantic
> analysis time.
>
> Ashish
>
> -----Original Message-----
> From: Shyam Sarkar [mailto:shyam_sar...@yahoo.com]
> Sent: Sunday, March 08, 2009 7:16 AM
> To: hive-dev@hadoop.apache.org
> Subject: Please check grammar for TIMESTAMP
>
> Hi Zheng and others,
>
> Could you please check Hive.g grammar changes for TIMESTAMP
> (See the comments with // Change by Shyam)?
> Please review and let me know your feedback. I shall write
> a short design doc later for review after these short
> exchanges.
>
> Thanks,
> shyam_sar...@yahoo.com
