Comments on: Cool SQL function: EXTRACT

By: Eddie Awad

Eddie Awad — Thu, 20 Mar 2008 18:30:15 +0000

@Gary: Good idea. Here is an example

select
    extract(hour from cast(sysdate as timestamp)) hh,
    extract(minute from cast(sysdate as timestamp)) mi,
    extract(second from cast(sysdate as timestamp))ss
from dual

Thanks.

By: Gary Menchen

Gary Menchen — Wed, 19 Mar 2008 20:41:15 +0000

You can cast a date to a timestamp and then extract the hour.

By: Glenn

Glenn — Wed, 19 Sep 2007 02:55:35 +0000

Well, this isn’t so useful if you want the name of the day instead of a number. Say, “MON” instead of 2. Back to TO_CHAR!

By: Rob Vollman

Rob Vollman — Thu, 29 Dec 2005 19:35:06 +0000

Yes, I just used this the other day. I wrapped it in a DECODE to get a text representation of the month.

By: Eddie Awad

Eddie Awad — Wed, 28 Dec 2005 17:57:23 +0000

you cannot extract Hour, minute or second from a date

Yes, the documentation says: The field you are extracting must be a field of the datetime_value_expr or interval_value_expr. For example, you can extract only YEAR, MONTH, and DAY from a DATE value.

I'm not sure exactly why you cannot get to the hour/minute/second from a DATE using EXTRACT, since a DATE datatype contains a time portion as well (but not fractional seconds).

It'll be interesting to know what the reason behind this limitation is.

By: FranÃ§ois

FranÃ§ois — Wed, 28 Dec 2005 15:12:40 +0000

You can also get this information with the To_Char() function.

SELECT to_char(SYSTIMESTAMP,'FF') FROM dual

By: Laurent Schneider

Laurent Schneider — Wed, 28 Dec 2005 14:36:36 +0000

interesting is extracting nanoseconds from timestamp :

SQL> create table t as select timestamp '2000-01-01 00:00:42.123456789' t from dual;

Table created.

SQL> select mod(extract(second from t),1)*1000000000 ns from t; NS

123456789

By: FranÃ§ois

FranÃ§ois — Wed, 28 Dec 2005 13:36:39 +0000

For an unknown reason you cannot extract Hour, minute or second from a date. It works only on Timestamp.
Francois