I wish to convert a single Oracle datetime value to minutes.
As an example, I need to convert the current date/time alone into minutes, i.e.:
select (sysdate)*24*60 from dual
but this is giving me an error.
I basically need to perform a check to see that a certain operation cannot be performed until 30 minutes before a particular date/start time, that exists in the database.
So if the Start Time in the DB is:
24/04/2014 22:00:00 and the current date/time (SYSDATE) is 24/04/2014 21:29:59,
then operation CANNOT be performed but if the current date/time (SYSDATE) is:
24/04/2014 21:30:00,
then operation CAN be performed.
You probably want something like
startTime - interval '30' minute >= sysdate
or
startTime >= sysdate + interval '30' minute
You could also subtract the two date values which gives you the number of days between them and multiply
(startTime - sysdate)*24*60 >= 30
but I generally find the interval notation clearer and easier to read. It's also easier to structure in a way that allows you to use indexes on columns like startTime.
select (sysdate - trunc(sysdate)) *24 *60 from dual
You seem to want to know if the seconds component of sysdate is 0. So, test for that:
where extract(second from sysdate) = 0
Oops, I misread the question. You just need a difference of 30 minutes. That is also easy:
where starttime <= sysdate + 30/(24*60)
When you add an integer to a datetime, it is interpreted as a number of days. The expression 30/(24*60) is an expression for half an hour measured in days.
Related
I have two timestamp columns: arrTime and depTime.
I need to find the number of munites the bus is late.
I tried the following:
SELECT RouteDate, round((arrTime-depTime)*1440,2) time_difference
FROM ...
I get the following error: inconsistent datatype . expected number but got interval day to second
How can i parse the nuber of minutes?
If i simply subtract: SELECT RouteDate, arrTime-depTime)*1440 time_difference
The result is correct but not well formatted:
time_difference
+00000000 00:01:00 0000000
The result of timestamp arithmetic is an INTERVAL datatype. You have an INTERVAL DAY TO SECOND there...
If you want the number of minutes one way would be to use EXTRACT(), for instance:
select extract( minute from interval_difference )
+ extract( hour from interval_difference ) * 60
+ extract( day from interval_difference ) * 60 * 24
from ( select systimestamp - (systimestamp - 1) as interval_difference
from dual )
Alternatively you can use a trick with dates:
select sysdate + (interval_difference * 1440) - sysdate
from (select systimestamp - (systimestamp - 1) as interval_difference
from dual )
The "trick" version works because of the operator order of precedence and the differences between date and timestamp arithmetic.
Initially the operation looks like this:
date + ( interval * number ) - date
As mentioned in the documentation:
Oracle evaluates expressions inside parentheses before evaluating those outside.
So, the first operation performed it to multiply the interval by 1,440. An interval, i.e. a discrete period of time, multiplied by a number is another discrete period of time, see the documentation on datetime and interval arithmetic. So, the result of this operation is an interval, leaving us with:
date + interval - date
The plus operator takes precedence over the minus here. The reason for this could be that an interval minus a date is an invalid operation, but the documentation also implies that this is the case (doesn't come out and say it). So, the first operation performed is date + interval. A date plus an interval is a date. Leaving just
date - date
As per the documentation, this results in an integer representing the number of days. However, you multiplied the original interval by 1,440, so this now represented 1,440 times the amount of days it otherwise would have. You're then left with the number of seconds.
It's worth noting that:
When interval calculations return a datetime value, the result must be an actual datetime value or the database returns an error. For example, the next two statements return errors:
The "trick" method will fail, rarely but it will still fail. As ever it's best to do it properly.
SELECT (arrTime - depTime) * 1440 time_difference
FROM Schedule
WHERE ...
That will get you the time difference in minutes. Of course, you can do any rounding that you might need to to get whole minutes....
Casting to DATE first returns the difference as a number, at least with the version of Oracle I tried.
round((cast(arrTime as date) - cast(depTime as date))*1440)
You could use TO_CHAR then convert back to a number. I have never tested the performance compared to EXTRACT, but the statement works with two dates instead of an interval which fit my needs.
Seconds:
(to_char(arrTime,'J')-to_char(depTime,'J'))*86400+(to_char(arrTime,'SSSSS')-to_char(depTime,'SSSSS'))
Minutes:
round((to_char(arrTime,'J')-to_char(depTime,'J'))*1440+(to_char(arrTime,'SSSSS')-to_char(depTime,'SSSSS'))/60)
J is julian day and SSSSS is seconds in day. Together they give an absolute time in seconds.
I have a database that contains a series of events and their timestamp.
I find myself needing to select all events that happen between 11:00 and 11:10 and 21:00 and 21:05, for all days.
So what I would do is I extract from timestamp the hour and the minute, and:
SELECT *
WHERE (hour = 11 AND minute <= 10)
OR (hour = 21 AND minute <= 05)
However, I was wondering if there's a simpler / less verbose way to do this, such as when you query between dates:
SELECT *
WHERE date BETWEEN '2020-07-01' AND '2020-07-05'
I read here that this is doable in SQLite, I was wondering if it's possible to be done in presto as well. I've looked at the docs but couldn't find an analogue function that does what time() does in SQLite.
You could use date formatting functions, e.g. date_format, then string comparisons:
select *
from mytable
where
date_format(mydate, '%H:%i') between '11:00' and '11:09'
or date_format(mydate, '%H:%i') between '21:00' and '21:04'
Note that I substracted one minute from the upper bound, since I assume you don't want to include the last minute. between '11:00' and '11:09' gives you everything from 11:00:00 to 11:09:59.
so I have a table called Value. I am trying to derive the Value for the last hour (HR --> Timestamp(4) with TIME ZONE ) so that I can use it in a conditional statement in this Stored Procedure that I'm building. However, when i try the following, Oracle only returns a Date (01-Jan-19) rather than the previous hour (01-Jan-19 01.00.00.00000000 AM UTC). What am I doing wrong?
select hr
, hr - (1/24) as Converted
from value;
If I try the following, I return '31-DEC-16 12.00.00.000000000 AM' as the value for 'Converted' (no matter what the value for HR is):
select hr
, to_timestamp(hr - (1/24)) as converted
from value;
Which ultimately will be used as the definition of a variable in my stored procedure:
select max(value)
into v_Previous_hour
from value
where hr = hr - (1/24);
Am I missing something here? Thanks in advance.
Try this:
select hr
, cast( hr - (1/24) as timestamp) as Converted
from value;
Also, the query below is not going to do what you think it is.
select max(value)
into v_Previous_hour
from value
where hr = hr - (1/24);
Or you could use INTERVAL:
SELECT TO_CHAR(HR) AS HR,
TO_CHAR(CAST(HR - INTERVAL '1' HOUR - INTERVAL '0.233' SECOND AS TIMESTAMP(4) WITH TIME ZONE)) AS HR_MINUS_ONE_HOUR
FROM VAL;
(Here I subtracted an additional 0.233 seconds just to make sure we were dealing with timestamps, per #AlexPoole's comment on #OldProgrammer's answer).
SQLFiddle here
Oracle only returns a Date (01-Jan-19)
A date still has a time, your client just isn't showing it to you. You can use to_char() to display it explicitly:
select to_char(hr - (1/24), 'YYYY-MM-DD HH24:MI:SS') from ...
It is a date because [that's the result of timestamp - number] arithmetic, and the timestamp is implicitly converted to a date before the subtraction. But you are losing both the fractional seconds and the time zone from your original value. Even if you cast back to a plain timestamp that information isn't recovered, and if you cast back to a timestamp with time zone it imolicitly picks up the current session's time zone, so won't necessarily match.
To keep both you can do what you suggested in your answer, or
select hr - interval '1' hour from ...
In your procedure, declare a variable of the same data type, e.g. (as an nonymous block):
declare
l_hr value.hr%type;
begin
select hr - interval '1' hour
into l_hr
from value
where ... ;
...
end;
Don't be tempted to store or manipulate the value as a string, keep it as its origial data type. It will be easieer to work with, safer and more efficient.
Have a look at this table Matrix of Datetime Arithmetic
When you perform {TIMESTAMP WITH TIME ZONE} - {NUMERIC} then you get DATE value, i.e. you loose the time zone information.
Better use INTERVAL, e.g. hr - INTERVAL '1' HOUR or hr - NUMTODSINTERVAL(1, 'HOUR')
Anyway, I don't understand your question. If you ask "How to grab the previous hour of a timestamp(4) with TIMEZONE column?" then my answer would be
SELECT
EXTRACT(HOUR FROM hr - INTERVAL '1' HOUR) AS Solution_1
TO_CHAR(hr - INTERVAL '1' HOUR, 'HH24') AS Solution_2
FROM ...
Note, solution EXTRACT(HOUR FROM hr - INTERVAL '1' HOUR) always returns the hour of UTC time, whereas TO_CHAR(hr - INTERVAL '1' HOUR, 'HH24') returns hour from the stored time zone.
After 2 hours of hairpulling (and ironically after OldProgrammer was nice enough to provide me with an answer), I found a workaround:
select hr
, hr - numtodsinterval(1, 'hour') as converted
from value;
By using normal minus '-' function between two timestamps, the answer given from oracle is incorrect.
This is what i want to do:
ALTER SESSION SET NLS_TIMESTAMP_TZ_FORMAT='DD-MON-RR HH24:MI TZR';
Created table:
CREATE TABLE TEST (
StartTime timestamp with time zone
,EndTime timestamp with time zone
,Science varchar2(7)
);
I create the column data type as timestamp with time zone. This is value I have inserted:
INSERT INTO TEST
VALUES('05-OCT-2013 01:00 +08:00'
,'05-OCT-2013 23:00 +06:00'
,'SCIENCE');
INSERT INTO TEST
VALUES('05-OCT-2013 12:00 +08:00'
,'05-OCT-2013 15:00 -12:00'
,'Maths');
Attempted for rounding time:
CREATE VIEW TESTRECRDS AS
SELECT (Extract(hour FROM(ENDTIME- STARTTIME)) || 'Hours' ||
Extract(minute FROM(ENDTIME- STARTTIME))>=60 Then (Extract(hour FROM(ENDTIME- STARTTIME)) + Extract(minute FROM(ENDTIME- STARTTIME))/60 ELSE 0 END || 'Minutes' AS DURATION,
Science
FROM Test;
Now i have two questions regarding on the calculation and rounding off the minutes to nearest hours.
First let's say the endtime is 1535 +0600 and starttime is 01:50 +0800
So when i deduct endtime - starttime:
the formula should be:
2135 - 0950 = 2085 - 0950
= 1135
But if i use my successful attempt answer to calculate, it is not the correct exact answer. The oracle answer would be 15 hours 45 minutes.
In your last CREATE VIEW statement you try to multiply text, which cannot work:
SELECT To_Char(STARTTIME - ENDTIME, 'HH24:MI TZR')*24 AS DURATION
*24 is operating on the text to_char() returns.
You have to multiply the interval before converting to text.
You define the column Science varchar2(6), then you insert 'SCIENCE', a 7-letter word?
I also fixed a syntax error in your INSERT statement: missing '.
About your comment:
"I would like to insert timestamp with timezone during creation of my tables. Can DATE data type do that too?
Read about data types in the manual.
The data type date does not include time zone information.
If by "timezone difference" you mean the difference between the timezone modifiers, use this to calculate:
SELECT EXTRACT(timezone_hour FROM STARTTIME) AS tz_modifier FROM tbl
Keywords here are timezone_hour and is timezone_minute. Read more in the manual.
But be aware that these numbers depend on the daylight saving hours and such shenanigans. Very uncertain territory!
Get it in pretty format - example:
SELECT to_char((EXTRACT (timezone_hour FROM STARTTIME) * 60
+ EXTRACT (timezone_minutes FROM STARTTIME))
* interval '1 min', 'HH:MI')
In PostgreSQL you would have the simpler EXTRACT (timezone FROM STARTTIME), but I don't think Oracle supports that. Can't test now.
Here is a simple demo how you could round minutes to hours:
SELECT EXTRACT(hour FROM (ENDTIME - STARTTIME))
+ CASE WHEN EXTRACT(minute FROM (ENDTIME - STARTTIME)) >= 30 THEN 1 ELSE 0 END
FROM Test;
I'm not sure what number you're trying to calculate, but when you subtract two dates in Oracle, you get the difference between the dates in units of days, not a DATE datatype
SELECT TO_DATE('2011-01-01 09:00', 'yyyy-mm-dd hh24:mi') -
TO_DATE('2011-01-01 08:00', 'yyyy-mm-dd hh24:mi') AS diff
FROM dual
DIFF
----------
.041666667
In this case 8am and 9am are 0.41667 days apart. This is not a date object, this is a scalar number, so formatting it as HH24:MI doesn't make any sense.
To round you will need to do a bit of more math. Try something like:
TO_DATE(ROUND((ENDTIME - STARTTIME) * 96) / 96, 'HH24:MI')
The difference between dates is in days. Multiplying by 96 changes the measure to quarter hours. Round, then convert back to days, and format. It might be better to use a numeric format want to format, in which case you would divide by 4 instead of 96.
Timezone is not particularly relevant to a time difference. You will have to adjust the difference from UTC to that timezone to get the right result with Timezone included.
Is there a TIMESTAMPDIFF() equivalent for PostgreSQL?
I know I can subtract two timestamps to get a postgresql INTERVAL. I just want the difference between the two timestamps in in hours represented by an INT.
I can do this in MySQL like this:
TIMESTAMPDIFF(HOUR, links.created, NOW())
I just need the difference between two timestamps in hours represented as an integer.
Solution works for me:
SELECT "links_link"."created",
"links_link"."title",
(EXTRACT(EPOCH FROM current_timestamp - "links_link"."created")/3600)::Integer AS "age"
FROM "links_link"
The first things popping up
EXTRACT(EPOCH FROM current_timestamp-somedate)/3600
May not be pretty, but unblocks the road. Could be prettier if division of interval by interval was defined.
Edit: if you want it greater than zero either use abs or greatest(...,0). Whichever suits your intention.
Edit++: the reason why I didn't use age is that age with a single argument, to quote the documentation: Subtract from current_date (at midnight). Meaning you don't get an accurate "age" unless running at midnight. Right now it's almost 1am here:
select age(current_timestamp);
age
------------------
-00:52:40.826309
(1 row)
Get fields where a timestamp is greater than date in postgresql:
SELECT * from yourtable
WHERE your_timestamp_field > to_date('05 Dec 2000', 'DD Mon YYYY');
Subtract minutes from timestamp in postgresql:
SELECT * from yourtable
WHERE your_timestamp_field > current_timestamp - interval '5 minutes'
Subtract hours from timestamp in postgresql:
SELECT * from yourtable
WHERE your_timestamp_field > current_timestamp - interval '5 hours'
Michael Krelin's answer is close is not entirely safe, since it can be wrong in rare situations. The problem is that intervals in PostgreSQL do not have context with regards to things like daylight savings. Intervals store things internally as months, days, and seconds. Months aren't an issue in this case since subtracting two timestamps just use days and seconds but 'days' can be a problem.
If your subtraction involves daylight savings change-overs, a particular day might be considered 23 or 25 hours respectively. The interval will take that into account, which is useful for knowing the amount of days that passed in the symbolic sense but it would give an incorrect number of the actual hours that passed. Epoch on the interval will just multiply all days by 24 hours.
For example, if a full 'short' day passes and an additional hour of the next day, the interval will be recorded as one day and one hour. Which converted to epoch/3600 is 25 hours. But in reality 23 hours + 1 hour should be a total of 24 hours.
So the safer method is:
(EXTRACT(EPOCH FROM current_timestamp) - EXTRACT(EPOCH FROM somedate))/3600
As Michael mentioned in his follow-up comment, you'll also probably want to use floor() or round() to get the result as an integer value.
You can use the "extract" or "date_part" functions on intervals as well as timestamps, but I don't think that does what you want. For example, it gives 3 for an interval of '2 days, 3 hours'. However, you can convert an interval to a number of seconds by specifying 'epoch' as the time element you want: extract(epoch from '2 days, 3 hours'::interval) returns 183600 (which you then divide by 3600 to convert seconds to hours).
So, putting this all together, you get basically Michael's answer: extract(epoch from timestamp1 - timestamp2)/3600. Since you don't seem to care about which timestamp precedes which, you probably want to wrap that in abs:
SELECT abs(extract(epoch from timestamp1 - timestamp2)/3600)
postgresql get seconds difference between timestamps
SELECT (
(extract (epoch from (
'2012-01-01 18:25:00'::timestamp - '2012-01-01 18:25:02'::timestamp
)
)
)
)::integer
which prints:
-2
Because the timestamps are two seconds apart. Take the number and divide by 60 to get minutes, divide by 60 again to get hours.
extract(hour from age(now(),links.created)) gives you a floor-rounded count of the hour difference.
To avoid the epoch conversion you could extract the days multiply them by 24 and add the extraction of hours to it.
select current_timestamp, (current_timestamp - interval '500' hour), (extract(day from (current_timestamp - (current_timestamp - interval '500' hour)) * 24) + extract(hour from (current_timestamp - (current_timestamp - interval '500' hour))));
For MySQL timestampdiff I don't know, but for MSSQL datediff(hour, start, end) the best equivalent in PostgreSQL is floor(extract(epoch from end - start)/3600), because in MSSQL select datediff(hour,'2021-10-31 18:00:00.000', '2021-10-31 18:59:59.999') return 0
This might sound crazy to a lot of developers who like to take advantage of database functions,
But after exhaustive problems thinking, creating and bugfixing applications for mysql and postgrsql with php comparing date functions, I've come to the conclusion (for myself), that the easiest way, that is the simplest with less SQL headaches is not to take advantage of any of them.
Why? because if you are developing in a middleware language like PHP, PHP has all of these functions, and they are easier to implement in the application ode as comparing integers. PostgreSQL timestamp is NOT == UNIX TIMESTAMP and MySQL's UNIX TIMESTAMP is NOT PostgresQL's or Oracles timestamp.. it gets harder to port if you use database timestamps..
so just use an integer, not a timestamp,
as the number of seconds since january 1st 1970 midnight. and never mind database timestamps.
, and use gmdate() and store everything as gmt time to avoid timezone issues.
if you need to search, sort or compare the day from other data, or the month or the year or the day of the week, or anything, in your application,
and INTEGER datatype for time_day, time_hour, time_seconds.. or whatever you wnat to index to be searched will make for smoother and more portable databases.
you can just use one field, in most instances: INTEGER time_created NOT NULL
(more fields in your database row is the only drawback to this solution that i have found, and that doesnt cause as many headaches, or cups of coffee :)
php's date functions are outstanding to compare dates,
but in mysql or postgresql, comparing dates ? nah.. use integer sql comparisons
i realize it may SEEM easier to use CURRENT_TIMESTAMP on an insert function. HA!
don't be fooled.
You cant do DELETE FROM SESSION_TABLE WHERE time-initialized < '2 days'
if time-intitialized is a postgresql timestamp.
but you CAN do:
DELETE FROM SESSION_TABLE WHERE time_initialized < '$yesterday'
As long as you set $yesterday in php as the integer of seconds since 1970 that yesterday was.
This is easier housekeeping of session records than comparing timestamps in postgresql select statements.
SELECT age(), SELECT extract(), and asbtime are headaches in an of themselves. this is just my opinion.
you can do addition, substraction, <, >, all with php date objects
_peter_sysko
U4EA Networks, Inc.