I get an error "date out of range for timestamp" in the following situation:
select '1000000-01-01'::date; --> 1000000-01-01 -> ok!
select extract(year from ('1000000-01-01'::date)) -> date out of range for timestamp
select to_char('1000000-01-01'::date, 'YYYY') -> date out of range for timestamp
I guess the problem is that somewhere the date is converted to timestamp.
How to extract the year in my situation?
Yeah, it seems any time you do an operation on a date it gets transformed to a timestamp. The best I could come up with:
select split_part('1000000-01-01', '-', 1) as year;
year
---------
1000000
--If value is actual date:
select split_part('1000000-01-01'::date::text, '-', 1) as year;
year
---------
1000000
Related
I have a database column giving me information on how often a file comes in.
Frequency_month
-------------
3rd Friday of the month
2nd Tuesday of the month
3rd Thursday of the month
I need to update this column and have it be a timestamp. e.g.
Frequency_month
-------------
2020-05-21 00:00:00
2020-05-11 00:00:00
2020-05-20 00:00:00
How can I accomplish this using postgres PLPGSQL language?
The following yields what your looking for. As far a parsing the Frequency_month it imposes the following restrictions:
The first character in the string is a digit indicating the relative
number.
This is followed 2 characters ordinal spec (st, nd, etc) and a space.
Actually any 3 characters, they are not checked.
Position 5 - 7 con the first 3 characters of the English day of week (dow).
If any of those are not satisfied you will need to change the S1 subquery.
Further it requires you to provide a date of reference. This may be any date in the month of interest. See comment by #sddk.
It proceeds as follows:
Parse the above extracting the week number, day of week, and last
day of the prior month. (S1).
Determine the ISODOW id numbers for the day of week specified and
DOW for last of prior month. (S2).
Using the ISODOW id numbers Determine, determine the first
occurrence of the target day in the target month. (S3).
Adjust the date from #3 by the additional weeks. (S4).
Finally, if the resulting date in #4 in still in the target month
return the date form #4. If it is not the same month then return
null. This occurs when there in no nth dow in the month or the dow
is incorrectly specified.
I have wrapped the above into a SQL function making parameterization easy. See Demo.
create or replace
function frequency_month( frequency_string text
, target_month date
)
returns date
language sql
as $$
with day_names( l_days) as
( values (array['mon','tue','wed','thu','fri','sat','sun']) )
select -- if the calculated date in still in the target month return that date else return null
-- covers invalid week in frequency 6th Friday or 0th Monday
case when extract(month from target_date) = extract (month from target_month)
then target_date
else null
end
from ( -- Advance from first dow in month the number of weeks to desirded dates
--select (first_of_mon + (7*(rel_num-1)) * interval '1 day')::date target_date
select (first_of_mon + (rel_num-1) * interval '1 week')::date target_date
from ( -- with last day of prior month get first DOW week of target month
select case when dow_day_nbr <= from_day_nbr
then (from_date + (dow_day_nbr-from_day_nbr+7) * interval '1 days' )::date
else (from_date + (dow_day_nbr-from_day_nbr) * interval '1 days' )::date
end first_of_mon
, rel_num
from ( -- Pick up ISODOW numbers
select array_position(l_days, (substring(to_char(from_date, 'day'),1,3))) as from_day_nbr
, array_position(l_days, lower(substring(rel_dow,1,3))) as dow_day_nbr
, from_date
, rel_num
from day_names
cross join ( -- get last day of prior month, desired relative day, relative dow
select substr(frequency_string,1,1)::integer rel_num
, lower(substr(frequency_string,5,3)) rel_dow
, (date_trunc('month',target_month) - interval '1 day')::date from_date
) s1
) s2
) s3
) s4;
$$;
Note: The demo also includes a standalone version if a function is not desired.
timestamp with timezone is this - 2020-05-31T10:05:07Z
this is not working, despite referencing official documentation. I need to extract may 2020 or separate month and year to compare against May 2020
SELECT date_trunc('hour', TIMESTAMP '2020-05-31T10:05:07Z')
SELECT date_part('day', TIMESTAMP '2020-05-31T10:05:07Z');
If you want to check if a timestamp value is "may 2020", you have different options.
to_char(the_value, 'yyyy-mm') = '2020-05'
or
extract(month from the_value) = 5
and extract(year from the_value) = 2020
or
(extract(month from the_value), extract(year from the_value)) = (5, 2020)
extract() and date_part() are the same thing - but I prefer the standard compliant extract() version.
demo:db<>fiddle
You need to_char() to format a date or timestamp. Mon gives you the first three letters of a month name:
SELECT
to_char(
TIMESTAMP '2020-05-31T10:05:07Z',
'Mon YYYY'
)
Returning the entire month name you can use Month instead of Mon. But, for some reasons, the length of the Month value is fixed to the longest month name available. That means May is returned with right padded spaces. To avoid this, you need to add the modifier FM:
SELECT
to_char(
TIMESTAMP '2020-05-31T10:05:07Z',
'FMMonth YYYY'
)
How to calculate end of the month in Postgres? I have table with column date datatype. I want to calculate end of the month of every date. For Eg. In the table there values like "2015-07-10 17:52:51","2015-05-30 11:30:19" then end of the month should be like 31 July 2015,31 May 2015.
Please guide me in this.
How about truncating to the beginning of this month, jumping forward one month, then back one day?
=# select (date_trunc('month', now()) + interval '1 month - 1 day')::date;
date
------------
2015-07-31
(1 row)
Change now() to your date variable, which must be a timestamp, per the docs. You can then manipulate this output (with strftime, etc.) to any format you need.
Source
SELECT TO_CHAR(
DATE_TRUNC('month', CURRENT_DATE)
+ INTERVAL '1 month'
- INTERVAL '1 day',
'YYYY-MM-DD HH-MM-SS'
) endOfTheMonth
Hi I tried like this and it worked
Date(to_char(date_trunc('month'::text, msm013.msa011) + '1 mon - 1 day '::interval , 'DD-MON-YYYY') )
Thanks a lot!!
Ive this query which return data for 30 days from current date , need to modify it to return data for current month only not 30 days from current date
SELECT count(1) AS counter FROM users.logged WHERE createddate >=
date_trunc('month', CURRENT_DATE);
any tips how to tweak this query , at based on Postgres
regards
Something like this should work.
SELECT count(1) AS counter
FROM users.logged
WHERE date_trunc('month', createddate) = date_trunc('month', current_date);
It is already supposed to return the values in current month. Truncation does the conversion 10 Nov 2013 14:16 -> 01 Nov 2013 00:00 and it will return the data since the beginning of this month. The problem seems to be something else.
Ive this query which return data for 30 days from current date , need to modify it to return data for current month only not 30 days from current date
That's incorrect. Your query:
SELECT count(1) AS counter FROM users.logged WHERE createddate >= date_trunc('month', CURRENT_DATE);
returns all dates >= Nov 1st 00:00:00, in other words what you say that you want already. Or then, you've simplified your query and left out the more important bits — those that are broken. If not:
It might be that you've dates in the future and that you're getting incorrect counts as a result. If so, add an additional criteria in the where clause:
AND created_date < date_trunc('month', CURRENT_DATE) + interval '1 month'
It might also be that your sample data has a bizarre row with a time zone such that it looks like the timestamp is from this month but the date/time arithmetics land it last month.
This is will give you data for the current month only. I try to extract month and year. The last step is you can compare created date against current date-time.
SELECT count(1) AS counter
FROM users.logged
WHERE
EXTRACT(MONTH FROM createddate) = EXTRACT(MONTH FROM current_date)
AND EXTRACT(YEAR FROM createddate) = EXTRACT(YEAR FROM current_date);
I got a table:
CREATE TABLE TRANSACTION (
transaction_date date,
id_transaction int,
PRIMARY KEY (id_transaction)
);
and I want to compare the month of 'transaction_date' field with a number of month.
SELECT *
FROM TRANSACTION T
WHERE month = transaction_date;
but I don't know how to make this conversion.
You can use EXTRACT(MONTH FROM transaction_date)
SELECT *
FROM transaction
WHERE EXTRACT(MONTH FROM transaction_date) = 1;
sqlfiddle demo
As per the documentation:
EXTRACT (field FROM source)
The extract function retrieves subfields such as year or hour from
date/time values. source must be a value expression of type timestamp,
time, or interval.
SELECT *
FROM TRANSACTION T
WHERE EXTRACT(MONTH FROM TIMESTAMP transaction_date) = month;
month should be an integer between 1 (January) and 12 (December).