In case of Oracle
the Query
select SYSDATE - TO_DATE('23-03-1022','dd-mm-yyyy') from dual;
is Giving the Output
SYSDATE-TO_DATE('23-03-1022','DD-MM-YYYY')
------------------------------------------
21715.2233
In case of EDB/Postgres it is-
select SYSDATE - TO_DATE('23-03-1022','dd-mm-yyyy') as date;
date
---------------------
21715 days 05:23:13
(1 row)
How can i get the Same output as oracle in case Of Postgres ?
What does .2233 tells in case of Oracle?
In Oracle, SYSDATE is a function that returns both date and time component. Difference of two DATE datatype values returns number of days between them. Therefore, as SYSDATE also contains hours, minutes and seconds, you'll almost always get a decimal number as the result (unless you run that piece of code at midnight).
Therefore, I presume that you'd - actually - want to truncate SYSDATE which then "removes" time component (sets it to 00:00:00):
SQL> select SYSDATE - TO_DATE('30-12-1899','dd-mm-yyyy') from dual;
SYSDATE-TO_DATE('30-12-1899','DD-MM-YYYY')
------------------------------------------
44715.3208
SQL> select trunc(SYSDATE) - TO_DATE('30-12-1899','dd-mm-yyyy') from dual;
TRUNC(SYSDATE)-TO_DATE('30-12-1899','DD-MM-YYYY')
-------------------------------------------------
44715
SQL>
As of 0.2279: it is - as I said - number of days. To quickly demonstrate it: if you want to get number of hours, you'd multiply it by 24 (the rest by 60 to get minutes, and its rest by 60 again to get seconds):
SQL> select 0.2279 * 24 as hours from dual;
HOURS
----------`enter code here`
5.4696
SQL> select 0.4696 * 60 as minutes from dual;
MINUTES
----------
28.176
SQL> select 0.176 * 60 as seconds from dual;
SECONDS
----------
10.56
SQL>
Which means that you ran that query today at 05:28:10.
Related
I need to substract 4 hours from CURRENT_TIMESTAMP in DB2, my query in SQL DEVELOPER is correct because I can see the registers I need to see, but when I do the query in Eclipse have some problem and I don't know which is. This is the query I need to do:
"SELECT yerror, COUNT(yerror) AS CantidadErrores FROM kexg.VD03154 WHERE tumod BETWEEN (CURRENT_TIMESTAMP - 4 HOUR) AND CURRENT_TIMESTAMP GROUP BY yerror;";
This query returns me an error but if I put 24 HOUR is correct. Also is correct if I put 5 DAYS for example.
I have try to subtract 04 HOUR, and it's wrong also.
Thanks in advance
The following works beautifully for me on DB2 for z/OS:
select current timestamp as rightnow,
current timestamp - 4 hours
from sysibm.sysdummy1
;
RIGHTNOW COL1
-------------------------- --------------------------
2020-02-27-08.16.55.142456 2020-02-27-04.16.55.142456
I have Oracle 12c DB table and one of it's column utc_timestamp is of type
UTC_TIMESTAMP TIMESTAMP(6) WITH TIME ZONE
It stores timestamp in UTC while current_timestamp and systimestamp both gives timestamp in different timezones.
How can I get time difference in MAX(utc_timestamp) and current_timestamp in minutes ignoring time difference due to different time zones.
For example:
select current_timestamp from dual;
Gives=> 23-AUG-17 04.43.16.253931000 PM AMERICA/CHICAGO
select systimestamp from dual;
Gives=> 23-AUG-17 05.43.16.253925000 PM -04:00
select max(UTC_TIMESTAMP) from table_name;
Gives=> 23-AUG-17 09.40.02.000000000 PM +00:00
For above condition when I run SQL to check time difference between in MAX(utc_timestamp) and current_timestamp I should get number 3.
I think I need something like:
select (extract(minute from current_timestamp) - extract(minute from max(UTC_TIMESTAMP)) * 1440) AS minutesBetween from table_name;
But different timezones are messing it up and I get negative number like -4317. This might be correct as current_timestamp will be higher than max(utc_timestamp) being in CST. So I tried:
select (extract(minute from CAST(current_timestamp as TIMESTAMP(6) WITH TIME ZONE)) - extract(minute from max(UTC_TIMESTAMP)) * 1440) AS minutesBetween from table_name;
This SQL runs without error but producing a big negative number like -83461. Please help me find what am I doing wrong.
You really have two problems here.
One is to convert CURRENT_TIMESTAMP to UTC. That is trivial:
select CURRENT_TIMESTAMP AT TIME ZONE 'UTC' from dual [.....]
(use the AT TIME ZONE clause https://docs.oracle.com/cd/B19306_01/server.102/b14225/ch4datetime.htm#i1007699)
The other is that the difference between two timestamps is an interval, not a number.
select current_timestamp at time zone 'UTC'
- to_timestamp_tz('24-AUG-17 04.00.00.000 AM UTC', 'dd-MON-yy hh.mi.ss.ff AM TZR')
from dual;
produces something like
+00 00:02:39.366000
which means + (positive difference) 00 days, 00 hours, 02 minutes, 39.366 seconds.
If you just want the minutes (always rounded down), you may wrap this whole expression within extract( minute from < ...... > ). Be aware though that the answer will still be 2 (minutes) even if the difference is five hours and two minutes. It is probably best to leave the result in interval data type, unless you are 100% sure (or more) that the result is always less than 1 hour.
The oracle last_day function return the last day of the month.
example:
nls_date_format='YYYY-MM-DD H24:MI:SS'
select last_day(sysdate) from dual;
LAST_DAY(SYSDATE)
-------------------
2014-06-30 15:45:43
oracle return the time value as well.
I have tried below sql in PostgreSQL which return the last day of month but time value is "00:00:00".
select (date_trunc('month', now()) + interval '1 month -1 day')::timestamp(0);
?column?
---------------------------
2014-06-30 00:00:00
(1 row)
the sql return the date correctly but I want date and time like oracle.
select (
date_trunc('month', now())
+ interval '1 month -1 day'
+ now()::time
)::timestamp(0);
The function last_day() should do the trick. This function should be found in a extenstion package called "orafce". Containing other functions used in Oracle.
Install the correct version of orafce package (if needed):
apt-get install postgresql-9.1-orafce
SQL:
Create Extension orafce
If error rename orafce--3.0.sql to orafce--3.03.sql or user later version of orafce.
Use the function:
SELECT last_day('2015-01-01')
Works like expected and the result is '2015-01-31'
I'm trying to get difference in days, casting result to decimal:
SELECT
CAST( TO_DATE('2999-01-01','yyyy-mm-dd') - TO_DATE('2909-01-01','yyyy-mm-dd') AS DECIMAL )
;
Now if I add 1 month to the 2nd date:
SELECT
CAST( TO_DATE('2999-01-01','yyyy-mm-dd') - (TO_DATE('2909-01-01','yyyy-mm-dd') + INTERVAL '1 MONTH' * (1) ) AS DECIMAL )
;
I'm getting an error:
ERROR: cannot cast type interval to numeric
OK, I can cast to char to get result:
SELECT
CAST( TO_CHAR( TO_DATE('2909-02-10','yyyy-mm-dd') - (TO_DATE('2909-01-01','yyyy-mm-dd') + INTERVAL '1 MONTH' * (1) ), 'DD') AS DECIMAL )
;
But in this case the 1st query modified with TO_CHAR casting stop working:
SELECT
CAST( TO_CHAR(TO_DATE('2999-01-01','yyyy-mm-dd') - TO_DATE('2909-01-01','yyyy-mm-dd'), 'DD') AS DECIMAL )
;
I'm getting ERROR: multiple decimal points.
So, my question is, how can I get days using the same sql statement? For both sql queries.
Look at your first two examples again. If you remove the outer CAST ... AS DECIMAL you get
?column?
----------
32872
?column?
------------
32841 days
Clearly the difference is in the "days". The second is an interval value rather than a simple number. You only want the number (because you always just want days) so you need to extract that part. Then you can cast to whatever precision you like:
SELECT extract(days FROM '32841 days'::interval)::numeric(9,2);
date_part
-----------
32841.00
Edit responding to Alexandr's follow-up:
Your first example fails with a fairly specific error:
SELECT extract(days FROM (TO_DATE('2999-01-01','yyyy-mm-dd') - TO_DATE('2909-01-01','yyyy-mm-dd'))::interval)::numeric(9,2);
ERROR: cannot cast type integer to interval
LINE 1: ...yyyy-mm-dd') - TO_DATE('2909-01-01','yyyy-mm-dd'))::interval...
Here you've got an integer (which is what you originally wanted) and try to cast it to an interval (for reasons I don't understand). It's complaining it doesn't know what units you want. You want 32872 what in your interval - seconds, hours, weeks, centuries?
The second example is complaining because you are trying to extract the "day" part from a simple integer, and of course there's no extract() function in the system to do that.
I think you probably need to take a step back and just take the time to understand the values your various expressions return.
Subtracting one date from another gives the number of days separating them - as an integer. There is no other sensible measure, really.
Adding (or subtracting) an interval to a date gives you a timestamp (without time zone) since the interval may contain whole days, days and hours, seconds etc.
Subtracting a timestamp from a date will give you an interval since the result may contain days, hours, seconds etc.
If you have an interval and you just want the days part then you use extract() on it and you will get an integer number of days back.
You will need an integer (or floating-point) number of days if you want to cast to numeric, not an interval because casting an interval to an scalar number makes no sense without units.
So - either stick to dates and date arithmetic (easy), or realise you are using timestamps (flexible) but understand which it is.
To get an illustration of what's happening you can do something like this (in psql):
CREATE TEMP TABLE tt AS SELECT
('2909-01-02'::date - '2909-01-01'::date) AS a,
('2909-01-02'::date - '2909-01-02 00:00:00'::timestamp) AS b;
\x
SELECT * FROM tt;
\d tt
That will show you the values and types you are dealing with. Repeat for as many columns as you find useful.
HTH
If you're doing interval arithmetic with dates, you should generally be using timestamps instead, as mentioned in the docs.
# SELECT extract(days FROM TO_TIMESTAMP('2999-01-01','yyyy-mm-dd') - TO_TIMESTAMP('2909-01-01','yyyy-mm-dd'))
date_part
-----------
32872
# SELECT extract(days FROM TO_TIMESTAMP('2999-01-01','yyyy-mm-dd') - (TO_TIMESTAMP('2909-01-01','yyyy-mm-dd') + '1 month'::interval) );
date_part
-----------
32841
The result of adding an interval to a date is actually a timestamp, not another date (the interval might have contained time portions), so you have to cast the result of the addition back down to date first:
SELECT
CAST( TO_DATE('2999-01-01','yyyy-mm-dd')
- CAST( (TO_DATE('2909-01-01','yyyy-mm-dd') + INTERVAL '1 MONTH' * (1) ) AS DATE)
AS DECIMAL )
I'm a bit of newbie when it comes to postgres, so bear with me a wee bit and i'll see if i can put up enough information.
i insert weather data into a table every 10 mins, i have a time column that is stamped with an epoch date.
I Have a column of the last hrs rain fall, and every hr that number changes of course with the running total (for that hour).
What i would like to do is skim through the rows to the end of each hour, and get that row, but do it over the last 4 hours, so i would only be returning 4 rows say.
Is this possible in 1 query? Or should i do multiple queries?
I would like to do this in 1 query but not fussed...
Thanks
Thanks guys for your answers, i was/am a bit confused by yours gavin - sorry:) comes from not knowing this terribly well.
I'm still a bit unsure about this, so i'll try and explain it a bit better..
I have a c program that inserts data into the database every 10 mins, it reads the data fom a device that keeps the last hrs rain fall, so every 10 mins it could go up by x amount.
So i guess i have 6 rows / hr of data.
My plan was to go back (in my php page) every 7, which would be the last entry for every hour, and just grab that value. Hence why i would only ever need 4 rows.. just spaced out a bit!
My table (readings) has data like this
index | time (text) | last hrs rain fall (text)
1 | 1316069402 | 1.2
All ears to better ways of storing it too :) I very much appreciate your help too guys thanks.
You should be able to do it in one query...
Would something along the lines of:
SELECT various_columns,
the_hour,
SUM ( column_to_be_summed )
FROM ( SELECT various_columns,
column_to_be_summed,
extract ( hour FROM TIME ) AS the_hour
FROM readings
WHERE TIME > ( NOW() - INTERVAL '4 hour' ) ) a
GROUP BY various_columns,
the_hour ;
do what you need?
SELECT SUM(rainfall) FROM weatherdata WHERE time > (NOW() - INTERVAL '4 hour' );
I don't know column names but that should do it the ones in caps are pgsql types. Is that what you are after?
I am not sure if this is exactly what you are looking for but perhaps it may serve as a basis for adaptation.
I often have a requirment for producing summary data over time periods though I don't use epoch time so there may be better ways of manipulating the values than I have come up with.
create and populate test table
create table epoch_t(etime numeric);
insert into epoch_t
select extract(epoch from generate_series(now(),now() - interval '6 hours',interval '-10 minutes'));
To divide up time into period buckets:
select generate_series(to_char(now(),'yyyy-mm-dd hh24:00:00')::timestamptz,
to_char(now(),'yyyy-mm-dd hh24:00:00')::timestamptz - interval '4 hours',
interval '-1 hour');
Convert epoch time to postgres timestamp:
select timestamptz 'epoch' + etime * '1 second'::interval from epoch_t;
then truncate to hour :
select to_char(timestamptz 'epoch' + etime * '1 second'::interval,
'yyyy-mm-dd hh24:00:00')::timestamptz from epoch_t
To provide summary information by hour :
select to_char(timestamptz 'epoch' + etime * '1 second'::interval,
'yyyy-mm-dd hh24:00:00')::timestamptz,
count(*)
from epoch_t
group by 1
order by 1 desc;
If you might have gaps in the data but need to report zero results use a generate_series to create period buckets and left join to data table.
In this case I create sample hour buckets back prior to the data population above - 9 hours instead of 6 and join on the conversion of epoch time to timestamp truncated to hour.
select per.sample_hour,
sum(case etime is null when true then 0 else 1 end) as etcount
from (select generate_series(to_char(now(),
'yyyy-mm-dd hh24:00:00')::timestamptz,
to_char(now(),'yyyy-mm-dd hh24:00:00')::timestamptz - interval '9 hours',
interval '-1 hour') as sample_hour) as per
left join epoch_t on to_char(timestamptz 'epoch' + etime * '1 second'::interval,
'yyyy-mm-dd hh24:00:00')::timestamptz = per.sample_hour
group by per.sample_hour
order by per.sample_hour desc;