In my oracle database, I am setting one date field like this
update abc set
startdate = CURRENT_TIMESTAMP AT TIME ZONE 'GMT'-TO_DSINTERVAL('0 00:59:00');
but when I do
select * from abc w where
w.startdate < CURRENT_TIMESTAMP AT TIME ZONE 'GMT'-TO_DSINTERVAL('0 00:59:00');
after a few minutes then it does not return this row.
To my surprise
select * from abc w where
w.startdate > CURRENT_TIMESTAMP AT TIME ZONE 'GMT'-TO_DSINTERVAL('0 00:59:00');
returns this row.
How is it possible?
Please help me understand.
From your comment
the data type of startdate is 'Date'. There is certainly some implicit conversion happening. The session is in PST. Is there any way we can stop or handle the implicit conversion?
CAST the right-hand side of the expression to a DATE rather than allowing an implicit cast to occur (which would cast the DATE value on the left-hand side to a TIMESTAMP WITH TIME ZONE data type with your current session time zone).
select *
from abc
where startdate < CAST(CURRENT_TIMESTAMP AT TIME ZONE 'GMT'-TO_DSINTERVAL('0 00:59:00') AS DATE);
db<>fiddle here
Related
I get the error message: ORA-01843: not a valid month after executing a sql plus script.
I try using the "standard" date format yyyy-mm-dd.
Is SQL/PL not understanding the alter session statement?
set linesize 200
set pagesize 1000
alter session set NLS_NUMERIC_CHARACTERS = ',.';
alter session set NLS_DATE_FORMAT = 'yyyy-mm-dd';
select
*
from my_table
where
date >= '2019-08-31';
exit
What you do need - from my point of view - is not to compare date values to strings.
Presuming that date here actually represent a DATE datatype column (why didn't you post table description?) (as already commented, you can't name a column that way, not unless you enclosed its name into double quotes), then
where date >= '2019-08-31'
---- ------------
DATE this is a string
datatype
Use date literal, which always has a DATE keyword and date in format 'yyyy-mm-dd':
where date >= date '2019-08-31'
Or, use to_date function with appropriate format mask:
where date >= to_date('2019-08-31', 'yyyy-mm-dd')
If date column (wrong name, as we already know) actually contains strings and you hope all of them are following the 'yyyy-mm-dd' format, well, some values don't. Storing dates into varchar2 datatype column is almost always a bad idea. Nobody prevents you from storing e.g. '2019-ac-31' into it, and that isn't a valid date value.
I'm just trying to fetch Hour of my table from created date in Oracle 12c Database but it is showing error INVALID EXTRACT FIELD FOR EXTRACT FIELD. kindly guide me to fetch hour of my date my code is here...
SELECT
EXTRACT( HOUR FROM (TO_CHAR(CREATED_DATE,'RRRR-MM-DD HH:MI:SS')) ) HOUR
FROM
INVOICE_V;
my Date is stored as 6/1/2020 4:04:50 PM in this format and Extract function is not accept this function.
Do not store dates as strings.
But, since you have, convert it from a string to a date using TO_DATE:
SELECT EXTRACT( HOUR FROM TO_TIMESTAMP(CREATED_DATE,'DD/MM/YYYY HH12:MI:SS AM') ) AS HOUR
FROM INVOICE_V;
If, however, you meant that its just displaying in that format (and is actually a DATE data type) then CAST the date to a timestamp:
SELECT EXTRACT( HOUR FROM CAST( CREATED_DATE AS TIMESTAMP) ) AS HOUR
FROM INVOICE_V;
An hour can not be used in the EXTRACT function.
The only way to extract hour is to use TO_CHAR or subtract it from TRUNC date as follows:
TO_CHAR(created_date,'HH24') -- OR 'HH' as per your requirement
-- OR
FLOOR(24*(created_date- TRUNC(created_date)))
Please note that Oracle does not store dates in any format. It has its own binary representation. What you see while selecting from the table is based on the NLS_DATE_FORMAT parameter.
You can set it according to your requirement.
ALTER SESSION SET NLS_dATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS'; -- like this
If you have a date column (or the-like), then:
select extract(hour from cast(created_date as timestamp)) as hr
from invoice_v
Alternatively:
select to_char(created_date, 'hh24') as hr
from invoice_v
The first expression returns an integer number, while the second produces a string.
Note that hour is a language keyword, hence not a good choice for an identifier (here, you used it as a column alias). I changed that.
For eg I have a student table with a DOJ(date of joining) column with its type set as DATE now in that I have stored records in dd-mon-yy format.
I have an IN param at runtime with date passed as string and its in dd/mm/yyyy format. How do I compare and fetch results on date?
I want to fetch count of records of students who have DOJ of 25-AUG-92 per my database table student, but I am getting date as varchar in dd/mm/yyyy format in an IN param, kindly please guide.
I have tried multiple options such as trunc, to_date, to_char but, unfortunately nothing seems to work.
I have a student table with a DOJ(date of joining) column with its type set as DATE now in that I have stored records in dd-mon-yy format.
Not quite, the DATE data-type does not have a format; it is stored internally in tables as 7-bytes (year is 2 bytes and month, day, hour, minute and second are 1-byte each). The user interface you are using (i.e. SQL/PLUS, SQL Developer, Toad, etc.) will handle the formatting of a DATE from its binary format to a human readable format. In SQL/Plus (or SQL Developer) this format is based on the NLS_DATE_FORMAT session parameter.
If the DATE is input using only the day, month and year then the time component is (probably) going to be set to 00:00:00 (midnight).
I have an IN param at runtime with date passed as string or say varchar and its in dd/mm/yyyy format. How do I compare and fetch results on date.?
Assuming the time component for you DOJ column is always midnight then:
SELECT COUNT(*)
FROM students
WHERE doj = TO_DATE( your_param, 'dd/mm/yyyy' )
If it isn't always midnight then:
SELECT COUNT(*)
FROM students
WHERE TRUNC( doj ) = TO_DATE( your_param, 'dd/mm/yyyy' )
or:
SELECT COUNT(*)
FROM students
WHERE doj >= TO_DATE( your_param, 'dd/mm/yyyy' )
AND doj < TO_DATE( your_param, 'dd/mm/yyyy' ) + INTERVAL '1' DAY
The below should do what you've described. If not, provide more information on how "nothing seems to work".
-- Get the count of students with DOJ = 25-AUG-1992
SELECT COUNT(1)
FROM STUDENT
WHERE TRUNC(DOJ) = TO_DATE('25/AUG/1992','dd/mon/yyyy');
The above was pulled from this answer. You may want to look at the answer, because if performance is critical to you, there is a different way to write this query which doesn't use trunc, which will allow Oracle to use index on DOJ, if one is present.
Though I am bit late in posting this but I have been able to resolve this.
What I did was I converted both the dates to_char in similar formats and it worked here is my query condition that worked..
TO_CHAR(TO_DATE(C.DOB, 'DD-MON-YY'),'DD-MON-YY')=TO_CHAR(TO_DATE(P_Dob,'DD/MM/YYYY'),'DD-MON-YY'))
Thanks for the support all. :)
I have a date type column in a table, where I store date along with time.
I want to query it by WHERE clause
I did it this way:
select *
from conference_hall_book
where to_date(end_time,'dd/mon/yyyy hh24:mi:ss') <= to_date('26/oct/2013 15:00:00','dd/mon/yyyy hh24:mi:ss')
But the result has 27/10/2013 8:00:00 AM also in end_time column.
Can any one help me finding the mistake?
The problem occurs because of
to_date(end_time,'dd/mon/yyyy hh24:mi:ss')
This is a wrong usage of the to_date function. To_date converts a string to a date.
When Oracle sees this expression, it will automatically convert the end_time value to a string, using the configured date format of your database/session. This format typically doesn't include the time part, so a date with the value of "27/10/2013 8:00:00 AM" will be converted to the string "27/10/2013" (if your database date format is dd/mm/yyyy).
Your to_date expression will then convert the string value "27/10/2013" back to a date. The resulting date value will be "27/10/2013 00:00:00", so you will have lost the time portion of your original date.
The simple and correct solution is to drop the to_date(end_time) expression and just use end_time. This will also ensure that if you have index on end_time, the query will be able to use that index.
select *
from conference_hall_book
where end_time <= to_date('26/oct/2013 15:00:00','dd/mon/yyyy hh24:mi:ss')
If I query my database with SELECT current_setting('TIMEZONE') I get 'UTC' (as expected).
Using PgAdmin, I run the following query:
SELECT foo FROM bar
PgAdmin shows "2011-03-12 08:00:00". However, when I read the value from Ruby (using DataMapper which uses the 'org.postgresql.Driver' JDBC driver as far as I know), it shows "2011-03-12 08:00:00 -0700".
Question: Where in the whole stack is the timezone getting added? Although I realize a lot depends on the specifics of my stack, it would really help to understand what should happen so that I can rule things out. For example, for a timestamp without time zone column, should I expect that JDBC driver gives a 'raw' value with no timezone information?
Something in Ruby is making the timezone adjustment:
psql=> select current_setting('timezone');
current_setting
-----------------
Canada/Pacific
(1 row)
psql=> select min(created_at) from people;
min
----------------------------
2010-07-09 13:58:51.320659
(1 row)
psql=> set timezone = 'utc';
psql=> select current_setting('timezone');
current_setting
-----------------
UTC
(1 row)
psql=> select min(created_at) from people;
min
----------------------------
2010-07-09 13:58:51.320659
(1 row)
You can check this by doing a raw SQL query of a timestamp from within Ruby and seeing what string you get back.
The JDBC driver when reading a timestamp without timezone makes bold/reasonable assumption that this timestamp is expressed in the JVM timezone.
If you do not want timezone to be added, use type 'timestamp without timezone'.
That way, reader will always read same second/hour/minute/day/month/year as you inserted.
I used following procedure to reproduce that
create table t (
without_tz timestamp without time zone ,
with_tz timestamp with time zone
)
SET SESSION TIME ZONE default;
insert into t VALUES ( now(), now() )
select * from t;
SET SESSION TIME ZONE PST8PDT;
insert into t VALUES ( now(), now() )
select * from t;
SET SESSION TIME ZONE PST6PDT;
insert into t VALUES ( now(), now() )
select * from t;
Observing values from select, I come to conclusion that
timestamp without timezone is never converted. You read same second/hour/minute/day/month/year what you inserted, no matter what timezone you are in.
timestamp with timezone converts values you read to your timezone. they represent same instant (point in time) but hour (and sometimes days, sometimes even minutes) values will be diffrent.