Reference Manual

From: "Jose' Soares Da Silva" <sferac(at)proxy(dot)bazzanese(dot)com>
To: pgsql-hackers(at)postgreSQL(dot)org, pgsql-docs(at)postgreSQL(dot)org
Subject: Reference Manual
Date: 1998-03-30 15:19:05
Message-ID: Pine.LNX.3.96.980330145248.417B-100000@proxy.bazzanese.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

Hi, all

I'm writing Reference Manual and I have two questions:

1 - Why PostgreSQL accept HOUR, MINUTE and SECOND to extract if from a
date ?

EXTRACT (field FROM date_expression)

There are no such fields on a date!

It make sense only for SQL92 syntax because it uses also time and interval
types:

EXTRACT -- extract a datetime field from a datetime or interval.

The possible values for field are:
- YEAR
- MONTH
- DAY
- HOUR
- MINUTE
- SECOND
- TIMEZONE_HOUR
- TIMEZONE_MINUTE

------------------------------------------------------------------------

2. - Seems that optional ALL keyword of UNION doesn't work.
The following query prints always the same result with and without
the ALL clause.

* UNION of two tables:

mytable: yourtable:
id|name id|name
--+------ --+------
1|Smith 1|Soares
2|Jones 2|Panini
3|Soares

SELECT mytable.id, mytable.name
FROM mytable
WHERE mytable.name LIKE 'S%'
UNION
SELECT yourtable.id, yourtable.name
FROM yourtable
WHERE yourtable.name LIKE 'S%';

this is the result even if I don't specify ALL.
id|name
--+------
1|Smith
1|Soares
3|Soares
---------
SQL92 says that result does not contain any duplicate rows anless
the ALL keyword is specified.

What's wrong with my example ?
Thanks, Jose'

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Bruce Momjian 1998-03-30 15:25:03 Re: [HACKERS] Reference Manual]
Previous Message Zeugswetter Andreas SARZ 1998-03-30 12:20:42 AW: [HACKERS] Optimizer fails?