Re: comparing datetime
- From: jo <jose.soares@xxxxxxxxxxxxxx>
- To: "Mark W. Farnham" <mwf@xxxxxxxx>, ORACLE-L <oracle-l@xxxxxxxxxxxxx>
- Date: Fri, 19 Apr 2013 09:11:17 +0200
here the output:
plan_table_output
------------------------------------------------------------------------------------------------
SQL_ID cv0jqbmyygwcw, child number 0
-------------------------------------
select data_invio_entrata from movimento_canina where
data_invio_entrata='2012-03-13
14:12:14.476865' and rownum <= 1
Plan hash value: 3444997322
------------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | Inst |
------------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | | | 2 (100)| | |
|* 1 | COUNT STOPKEY | | | | | | |
|* 2 | TABLE ACCESS FULL| MOVIMENTO_CANINA | 2 | 24 | 2 (0)| 00:00:01 |
VETER~ |
------------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter(ROWNUM<=1)
2 -
filter(SYS_EXTRACT_UTC("DATA_INVIO_ENTRATA")=SYS_EXTRACT_UTC(TO_TIMESTAMP_TZ('201
2-03-13 14:12:14.476865')))
(22 rows)
----------------------------------------------------------------------------------------------
It uses SYS_EXTRACT_UTC to compare values. I tried this:
SQL> select DATA_INVIO_ENTRATA from movimento_canina where
SYS_EXTRACT_UTC(to_timestamp_tz('2012-03-13 14:12:14.476865')) =
SYS_EXTRACT_UTC(DATA_INVIO_ENTRATA);
data_invio_entrata
--------------------------
(0 rows)
SQL> select DATA_INVIO_ENTRATA from movimento_canina where
SYS_EXTRACT_UTC(to_timestamp_tz('2012-03-13 14:12:14.476865')) =
SYS_EXTRACT_UTC(to_timestamp_tz(DATA_INVIO_ENTRATA)) limit 1;
data_invio_entrata
--------------------------
2012-03-13 14:12:14.476865
(1 rows)
How can I change the filter used by oracle to compare datetimes?
desc:
name | type
--------------------------+ ---------------------------
id | number
data_invio_entrata | timestamp(6) with time zone
j
Mark W. Farnham wrote:
> What you're showing is the plan for display_cursor itself. I suspect you
> were debugging it to work in your release.
>
> Run the query with the timestamp, then run the display_cursor. In 10 the
> default is the previously executed query, so it should work for you.
> A filter line should show up in the query that shows you how the predicate
> is interpreted into an explicit representation from your implicit string
> conversion.
>
> I don't have a good portable solution for you unless the literal timestamp
> format the other fellow in the thread suggested works for all the databases
> you need to hit.
> Using the cast function (or any function) against the table's column will
> have the effect of running the function on each row returned. If you can
> cast the literal as a timestamp to match the column the literal only has to
> be handled once.
>
> good luck,
>
> mwf
>
> -----Original Message-----
> From: jo [mailto:jose.soares@xxxxxxxxxxxxxx]
> Sent: Thursday, April 18, 2013 6:09 AM
> To: mwf@xxxxxxxx
> Subject: Re: comparing datetime
>
> Hi Mark,
>
> I changed your query as:
>
> select * from table(dbms_xplan.display_cursor);
>
> and there is thi output...could you see anything helpful?
>
>
> plan_table_output
> ----------------------------------------------------------------------------
> -
> SQL_ID dt0hqkzcdq5ny, child number 0
> -------------------------------------
> select * from table(dbms_xplan.display_cursor)
>
> Plan hash value: 3713220770
>
> ----------------------------------------------------------------------------
> -
> | Id | Operation | Name | Cost | Inst |
> ----------------------------------------------------------------------------
> -
> | 0 | SELECT STATEMENT | | 24 | |
> | 1 | COLLECTION ITERATOR PICKLER FETCH| DISPLAY_CURSOR | | VETER~ |
> ----------------------------------------------------------------------------
> -
>
> Note
> -----
> - cpu costing is off (consider enabling it)
>
> (17 rows)
>
>
> Mark W. Farnham wrote:
>
>> You really don't want to run the function on the column for each row.
>> You want to get the timestamp literal either with the to_timestamp
>> function with the flexible formatting options or in the form the other
>>
> fellow suggested.
>
>> Unless you're trying to avoid using an index on the timestamp column
>> or feel a need to give your cpu a little extra exercise, then cast
>> your column all you want, but that is going to do extra work on each
>> row, which is a bad habit that can be significant.
>>
>> What release are you on that dbms_xplan.display_cursor is not working?
>> Perhaps you need to enable something. Good lord, I take that being
>> available as a given and I don't know how people live without it.
>>
>> mwf
>>
>> -----Original Message-----
>> From: oracle-l-bounce@xxxxxxxxxxxxx
>> [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
>> On Behalf Of jo
>> Sent: Thursday, April 18, 2013 2:50 AM
>> Cc: oracle-l@xxxxxxxxxxxxx
>> Subject: Re: comparing datetime
>>
>> Hi Mark,
>>
>> I resolved the question by using CAST...
>>
>> SELECT ts_ultima_modifica FROM movimento_canina WHERE
>> CASTcast(ts_ultima_modifica AS TIMESTAMP)='2013-04-11
>> 10:14:52.782680';
>>
>> thanks for the help anyway.
>>
>> ps:
>>
>> by the way, the query
>> select * from table(dbms_xplan.display_cursor(format=>'ALLSTATS
>> LAST')); doesn't work.
>>
>>
>>
>> Mark W. Farnham wrote:
>>
>>
>>> If you want an explicit conversion of a constant to a timestamp, use
>>> to_timestamp:
>>>
>>> to_timestamp('2012-03-13 14:12:14.476865','YYYY-MM-DD
>>> HH24:MI:SS.FFTZD')
>>>
>>> If you want to see what your query is using for an implicit timestamp
>>> conversion, then run your query and then run
>>>
>>> select * from table(dbms_xplan.display_cursor(format=>'ALLSTATS
>>> LAST'));
>>>
>>> and you should see the comparison actually being done in a filter
>>>
>>>
>> statement.
>>
>>
>>> Then, seeing what Oracle is doing might help you see what is wrong.
>>>
>>> -----Original Message-----
>>> From: oracle-l-bounce@xxxxxxxxxxxxx
>>> [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
>>> On Behalf Of Jose Soares
>>> Sent: Wednesday, April 17, 2013 8:59 AM
>>> To: oracle-l@xxxxxxxxxxxxx
>>> Subject: comparing datetime
>>>
>>> Hi all,
>>>
>>> I'm having some troubles comparing datetimes in oracle... what's
>>> wrong with these queries:
>>>
>>>
>>> file: login.sql
>>>
>>> alter session set nls_timestamp_tz_format='YYYY-MM-DD
>>> HH24:MI:SS.FFTZD';
>>>
>>> select codice_bdn,data_invio_entrata from movimento_canina join
>>> tipo_movimento_canina on
>>> tipo_movimento_canina.codice=cod_tipo_movimento_entrata and
>>> data_invio_entrata>'2012-03-13 14:12:14.476865' and rownum = 1;
>>>
>>> select codice_bdn,data_invio_entrata from movimento_canina join
>>> tipo_movimento_canina on
>>> tipo_movimento_canina.codice=cod_tipo_movimento_entrata and
>>> data_invio_entrata='2012-03-13 14:12:14.476865' and rownum = 1;
>>>
>>> select codice_bdn,data_invio_entrata from movimento_canina join
>>> tipo_movimento_canina on
>>> tipo_movimento_canina.codice=cod_tipo_movimento_entrata and
>>> data_invio_entrata<'2012-03-13 14:12:14.476865' and rownum = 1;
>>>
>>>
>>>
>>> $ sqlplus uri
>>>
>>> Session altered.
>>>
>>> CODI DATA_INVIO_ENTRATA
>>> ----
>>>
>>>
>>>
>> ----------------------------------------------------------------------
>> -----
>>
>>
>>> 0 2012-03-13 14:12:14.476865
>>>
>>> no rows selected
>>>
>>> no rows selected
>>>
>>> SQL>
>>>
>>> Why data_invio_entrata > '2012-03-13 14:12:14.476865' if they
>>> contains the same value?
>>> j
>>>
>>> --
>>> //www.freelists.org/webpage/oracle-l
>>>
>>>
>>> --
>>> //www.freelists.org/webpage/oracle-l
>>>
>>>
>>>
>>>
>>>
>>
>>
>
>
>
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