PostgreSQL: How to get last 2 years of data from today's date - postgresql

I am using PostgreSQL and need to know how to get data from last 2 years starting today, which is current_date.
Is my query correct ?
select count(*) from table_name where
creation_date >= date_trunc('year', now()) - interval '2' year and
creation_date < date_trunc('year', now());

Assuming you want a two year span starting from the current date:
select count(*) from table_name where
creation_date >= current_date - interval '2' year and
creation_date < current_date;
Using current_date eliminates the need to truncate now().

What About Extracting only Year from the two parts and make just little comparaison like that;
select count(*) from table_name where
EXTRACT(YEAR FROM CURRENT_DATE) - EXTRACT(YEAR FROM creation_date) BETWEEN 0 and 2

Related

Fetch records of current month using PostgreSQL query

Suppose I have following data in a table
id createdAt
1 2021-02-26T06:29:03.482Z
2 2021-02-27T06:29:03.482Z
3 2021-03-14T06:29:03.482Z
4 2021-03-17T06:29:03.482Z
I want data of current month. ie, if I generate report in march, I need to fetch results of march, so we need only current month data from table.
wanted output is
id createdAt
3 2021-03-14T06:29:03.482Z
4 2021-03-17T06:29:03.482Z
Anyone please help. Thank you.
You can use date_trunc():
select *
from the_table
where date_trunc('month', createdat) = date_trunc('month', current_timestamp);
date_trunc('month', ...) returns the first day of the month.
However, the above is not able to make use of an index on createdat. To improve performance, use a range query:
select *
from the_table
where createdat >= date_trunc('month', current_timestamp)
and createdat < date_trunc('month', current_timestamp) + interval '1 month'
The expression date_trunc('month', current_timestamp) + interval '1 month' returns the start of the next month (that's way this is compared with <)
You can compare the month and year of a date with the current one. But the index by field will not be used, you can build a separate index by year and month for this.
select *
from your_table
where extract(YEAR FROM createdAt) = extract(YEAR FROM now())
and extract(MONTH FROM createdAt) = extract(MONTH FROM now())

PostgreSQL Extract Year from Timestamp and then apply Interval Calculation

I'd like to filter a dataset to include everything with a created_date >= current year plus 5 full years prior. If I ran this today, I'd want anything with a created_date >= 01/01/2016 (2021 - 5 = 2016)
where extract(year from created_date) >= extract(year from current_date) - interval '5 years'
of course this doesn't work with double precision datatype. Any thoughts? Thank you.
Use date_trunc() to "round" the dates to the first of January.
where date_trunc('year', created_date) >= date_trunc('year', current_timestamp) - interval '5 years'
But the "I'd want anything with a created_date >= 01/01/2016" seems to indicate you might want:
where created_date >= date_trunc('year', current_timestamp) - interval '5 years'

How to find Last Week entries and This Week entries from postgres tables

I want to find the LastWeek entries from postgres table with cycle from Monday to Sunday (both inclusive) For eg - if I query the data today i.e on 2020/07/26 (or say if i query data on any date between 2020/07/20 to 2020/07/26) i should get the data from 2020/07/13 to 2020/07/19
Query:
Select user, date_sent
from users
where date_sent between (SELECT current_date - cast(extract(dow from current_date) as int) - 6)
and (SELECT current_date - cast(extract(dow from current_date) as int) + 1)
Similarly I want to find the This Week entries week starting from Monday and ending on present date. For eg - If I query the data today i.e on 2020/07/26 I should get the data from 2020/07/20 to 2020/07/26. If i query on 2020/07/24 then I should get 2020/07/20 to 2020/07/24
Query:
select user, date_sent
from users
where date_sent >= date_trunc('week', current_date)
and date_sent <= date_trunc('day',current_date+1)
You are almost there.
For "this week":
select user, date_sent
from users
where date_sent >= date_trunc('week', current_date)
and date_sent < date_trunc('week', current_date) + interval '1 week';
For last week it's quite similar:
select user, date_sent
from users
where date_sent >= date_trunc('week', current_date) - interval '1 week'
and date_sent < date_trunc('week', current_date)
Your desired results are inconsistent. In your description, before your initial query you state:
if I query the data today i.e on 2020/07/26 (or say if i query data on
any date between 2020/07/20 to 2020/07/26) i should get the data from
2020/07/13 to 2020/07/19
But after that query you state:
If I query the data today i.e on 2020/07/26 I should get the data from
2020/07/20 to 2020/07/26.
You cannot have both.
Assuming the latter to be correct and assuming ISO-8601 week definition, then your request can be re-phased as:
Given a specified date, if that date falls in the same week as the
current date then return the dates from the start of the week to the
specified date, inclusive. If the specified date does not fall in the
current week return the dates return the dates from Monday on or prior
to the specified date through Sunday on or after the specified date, inclusive.
The following implements that.
with targets (for_week_containing_date
,from_week_start
,iso_from_week
,iso_this_week) as
( select &for_week_containing_date
, date_trunc('week', &for_week_containing_date)
, extract(week from &for_week_containing_date)
, extract(week from now())
)
select user, date_sent
from user_days
cross join targets
where 1=1
and date_sent >= from_week_start
and date_sent <= case when iso_from_week = iso_this_week
then for_week_containing_date
else from_week_start + interval '6 days'
end
;
Since I do not care much for substitution variables this would need bound variables from a script, or wrap wrap it in an SQL function. See example of that here. Also note the last 2 queries, make sure you are ok with and understand what's happening around year end. You may need to make end of year/ begin of year adjustments. The results are not from being in a function, but result from ISO-8601 definitions. End of year/Begin year checking is needed any time you deal with date ranges.

Generate dates for postgres

i have a table
and i have a range from '2019-01-02' to '2019-01-04'
I need to generate ID and DATES (generated) from my table which started_at and ended_at (nullable) between the given range
result must be like this:
ID 4 from table is not included in result because it's started_at and ended_at not in range '2019-01-02' and '2019-01-04'
I need query that will do that in postgres.
Use generate_series()
select t.id, g.dt::date
from the_table t
cross join generate_series(t.started_at::date + 1,
least(t.ended_at::date, date '2019-01-04'),
interval '1 day') as g(dt)
where t.started_at >= date '2019-01-02'
and t.started_at < date '2019-01-04';
Worked this variant:
select t.id, g.dt::date from the_table t
cross join generate_series(t.started_at::date + 1,
least(t.ended_at::date, date '2019-01-04'), interval '1 day') as g(dt)
where dt >= date '2019-01-02' and dt < date '2019-01-04';

Postgres birthdays selection

I work with a Postgres database. This DB has a table with users, who have a birthdate (date field). Now I want to get all users who have their birthday in the upcoming week....
My first attempt: SELECT id FROM public.users WHERE id IN (lange reeks) AND birthdate > NOW() AND birthdate < NOW() + interval '1 week'
But this does not result, obviously because off the year. How can I work around this problem?
And does anyone know what happen to PG would go with the cases at 29-02 birthday?
We can use a postgres function to do this in a really nice way.
Assuming we have a table people, with a date of birth in the column dob, which is a date, we can create a function that will allow us to index this column ignoring the year. (Thanks to Zoltán Böszörményi):
CREATE OR REPLACE FUNCTION indexable_month_day(date) RETURNS TEXT as $BODY$
SELECT to_char($1, 'MM-DD');
$BODY$ language 'sql' IMMUTABLE STRICT;
CREATE INDEX person_birthday_idx ON people (indexable_month_day(dob));
Now, we need to query against the table, and the index. For instance, to get everyone who has a birthday in April of any year:
SELECT * FROM people
WHERE
indexable_month_day(dob) >= '04-01'
AND
indexable_month_day(dob) < '05-01';
There is one gotcha: if our start/finish period crosses over a year boundary, we need to change the query:
SELECT * FROM people
WHERE
indexable_month_day(dob) >= '12-29'
OR
indexable_month_day(dob) < '01-04';
To make sure we match leap-day birthdays, we need to know if we will 'move' them a day forward or backwards. In my case, it was simpler to just match on both days, so my general query looks like:
SELECT * FROM people
WHERE
indexable_month_day(dob) > '%(start)%'
%(AND|OR)%
indexable_month_day(dob) < '%(finish)%';
I have a django queryset method that makes this all much simpler:
def birthday_between(self, start, finish):
"""Return the members of this queryset whose birthdays
lie on or between start and finish."""
start = start - datetime.timedelta(1)
finish = finish + datetime.timedelta(1)
return self.extra(where=["indexable_month_day(dob) < '%(finish)s' %(andor)s indexable_month_day(dob) > %(start)s" % {
'start': start.strftime('%m-%d'),
'finish': finish.strftime('%m-%d'),
'andor': 'and if start.year == finish.year else 'or'
}]
def birthday_on(self, date):
return self.birthday_between(date, date)
Now, I can do things like:
Person.objects.birthday_on(datetime.date.today())
Matching leap-day birthdays only on the day before, or only the day after is also possible: you just need to change the SQL test to a `>=' or '<=', and not adjust the start/finish in the python function.
I'm not overly confident in this, but it seems to work in my testing. The key here is the OVERLAPS operator, and some date arithmetic.
I assume you have a table:
create temporary table birthdays (name varchar, bday date);
Then I put some stuff into it:
insert into birthdays (name, bday) values
('Aug 24', '1981-08-24'), ('Aug 04', '1982-08-04'), ('Oct 10', '1980-10-10');
This query will give me the people with birthdays in the next week:
select * from
(select *, bday + date_trunc('year', age(bday)) + interval '1 year' as anniversary from birthdays) bd
where
(current_date, current_date + interval '1 week') overlaps (anniversary, anniversary)
The date_trunc truncates the date at the year, so it should get you up to the current year. I wound up having to add one year. This suggests to me I have an off-by-one in there for some reason. Perhaps I just need to find a way to get dates to round up. In any case, there are other ways to do this calculation. age gives you the interval from the date or timestamp to today. I'm trying to add the years between the birthday and today to get a date in the current year.
The real key is using overlaps to find records whose dates overlap. I use the anniversary date twice to get a point-in-time.
Finally, to show the upcoming birthdays of the next 14 days I used this:
SELECT
-- 14 days before birthday of 2000
to_char( to_date(to_char(c.birthdate, '2000-MM-dd'), 'YYYY-MM-dd') - interval '14 days' , 'YYYY-MM-dd') as _14b_b2000,
-- birthday of 2000
to_date(to_char(c.birthdate, '2000-MM-dd'), 'YYYY-MM-dd') as date_b2000,
-- current date of 2000
to_date(to_char(current_date, '2000-MM-dd'), 'YYYY-MM-dd') as date_c2000,
-- 14 days after current date of 2000
to_char( to_date(to_char(current_date, '2000-MM-dd'), 'YYYY-MM-dd') + interval '14 days' , 'YYYY-MM-dd') as _14a_c2000,
-- 1 year after birthday of 2000
to_char( to_date(to_char(c.birthdate, '2000-MM-dd'), 'YYYY-MM-dd') + interval '1 year' , 'YYYY-MM-dd') as _1ya_b2000
FROM c
WHERE
-- the condition
-- current date of 2000 between 14 days before birthday of 2000 and birthday of 2000
to_date(to_char(current_date, '2000-MM-dd'), 'YYYY-MM-dd') between
to_date(to_char(c.birthdate, '2000-MM-dd'), 'YYYY-MM-dd') - interval '14 days' and
to_date(to_char(c.birthdate, '2000-MM-dd'), 'YYYY-MM-dd')
or
-- 1 year after birthday of 2000 between current date of 2000 and 14 days after current date of 2000
to_date(to_char(c.birthdate, '2000-MM-dd'), 'YYYY-MM-dd') + interval '1 year' between
to_date(to_char(current_date, '2000-MM-dd'), 'YYYY-MM-dd') and
to_date(to_char(current_date, '2000-MM-dd'), 'YYYY-MM-dd') + interval '14 days'
;
So:
To solve the leap-year issue, I set both birthdate and current date to 2000,
and handle intervals only from this initial correct dates.
To take care of the near end/beginning dates,
I compared first the 2000 current date to the 2000 birthday interval,
and in case current date is at the end of the year, and the birthday is at the beginning,
I compared the 2001 birthday to the 2000 current date interval.
Here's a query that gets the right result, most of the time.
SELECT
(EXTRACT(MONTH FROM DATE '1980-08-05'),
EXTRACT(DAY FROM DATE '1980-08-05'))
IN (
SELECT EXTRACT(MONTH FROM CURRENT_DATE + s.a) AS m,
EXTRACT(DAY FROM CURRENT_DATE + s.a) AS d
FROM GENERATE_SERIES(0, 6) AS s(a)
);
(it doesn't take care of leap years correctly; but you could use extract again to work the subselect in terms of a leap year instead of the current year.
EDIT: Got it working for all cases, and as a useful query rather than a scalar select. I'm using some extra subselects so that I don't have to type the same date or expression twice for month and day, and of course the actual data would be in a table instead of the values expression. You might adapt this differently. It might still stand to improve by making a more intelligent series for weeks containing leap days, since sometimes that interval will only contain 6 days (for non-leap years).
I'll try to explain this from the inside-out; First thing I do is normalize the target date (CURRENT_DATE usually, but explicit in this code) into a year that I know is a leap year, so that February 29th appears among dates. The next step is to generate a relation with all of the month-day pairs that are under consideration; Since there's no easy way to do an interval check in terms of month-day, it's all happening using generate_series,
From there it's a simple matter of extracting the month and day from the target relation (the people alias) and filtering just the rows that are in the subselect.
SELECT *
FROM
(select column1 as birthdate, column2 as name
from (values
(date '1982-08-05', 'Alice'),
(date '1976-02-29', 'Bob'),
(date '1980-06-10', 'Carol'),
(date '1992-06-13', 'David')
) as birthdays) as people
WHERE
((EXTRACT(MONTH FROM people.birthdate),
EXTRACT(DAY FROM people.birthdate)) IN (
SELECT EXTRACT(MONTH FROM thedate.theday + s.a) AS m,
EXTRACT(DAY FROM thedate.theday + s.a) AS d
FROM
(SELECT date (v.column1 -
(extract (YEAR FROM v.column1)-2000) * INTERVAL '1 year'
) as theday
FROM (VALUES (date '2011-06-09')) as v) as thedate,
GENERATE_SERIES(0, 6) AS s(a)
)
)
Operating on days, as I've done here, should work splendidly all the way up until a two month interval (if you wanted to look out that far), since december 31 + two months and change should include the leap day. On the other hand, it's almost certainly more useful to just work on whole months for such a query, in which case you don't really need anything more than extract(month from ....
First find out how old the person currently is using age(), then grab the year from that extract(year from age()). This is how old they are currently in years, so for their age at their next birthday add 1 to the year. Then their next birthday is found by adding an interval of this many years * interval '1 year' to their birthday. Done.
I've used a subselect here to add the next_birth_day column in to the complete table to make the select clause simpler. You can then play with the where conditions to suit your needs.
select *
from (
select *,
(extract(year from age(birth_date)) + 1) * interval '1 year' + birth_date "next_birth_day"
from public.users
) as users_with_upcoming_birth_days
where next_birth_day between now() and now() + '7 days'
This is based on Daniel Lyons's anniversary idea, by calculating the interval between the next birthday and today, with just +/- date arithmetic:
SELECT
today,
birthday,
CASE
WHEN this_year_anniversary >= today
THEN this_year_anniversary
ELSE this_year_anniversary + '1 year'::interval
END - today < '1 week'::interval AS is_upcoming
FROM
(
SELECT
today,
birthday,
birthday + years AS this_year_anniversary
FROM
(
SELECT
today,
birthday,
((
extract(year FROM today) - extract(year from birthday)
) || ' years')::interval AS years
FROM
(VALUES ('2011-02-28'::date)) AS t1 (today),
(VALUES
('1975-02-28'::date),
('1975-03-06'::date),
('1976-02-28'::date),
('1976-02-29'::date),
('1976-03-06'::date)
) AS t2 (birthday)
) AS t
) AS t;
In case you want it to work with leap years:
create or replace function birthdate(date)
  returns date
as $$
  select (date_trunc('year', now()::date)
         + age($1, 'epoch'::date)
         - (extract(year from age($1, 'epoch'::date)) || ' years')::interval
         )::date;
$$ language sql stable strict;
Then:
where birthdate(birthdate) between current_date
and current_date + interval '1 week'
See also:
Getting all entries who's Birthday is today in PostgreSQL
Exemple: birthdate between: jan 20 and feb 10
SELECT * FROM users WHERE TO_CHAR(birthdate, '1800-MM-DD') BETWEEN '1800-01-20' AND '1800-02-10'
Why 1800?
No matter may be any year;
In my registration form, I can inform the date of birth (with years) or just the birthday (without year), in which case I saved as 1800 to make it easier to work with the date
Here's my take, which works with leap years too:
CREATE OR REPLACE FUNCTION days_until_birthday(
p_date date
) RETURNS integer AS $$
DECLARE
v_now date;
v_days integer;
v_date_upcoming date;
v_years integer;
BEGIN
v_now = now()::date;
IF (p_date IS NULL OR p_date > v_now) THEN
RETURN NULL;
END IF;
v_years = date_part('year', v_now) - date_part('year', p_date);
v_date_upcoming = p_date + v_years * interval '1 year';
IF (v_date_upcoming < v_now) THEN
v_date_upcoming = v_date_upcoming + interval '1 year';
END IF;
v_days = v_date_upcoming - v_now;
RETURN v_days;
END
$$ LANGUAGE plpgsql IMMUTABLE;
I know this post is old, but I had the same issue and came up with this simple and elegant solution:
It is pretty easy with age() and accounts for lap years... for the people who had their birthdays in the last 20 days:
SELECT * FROM c
WHERE date_trunc('year', age(birthdate)) != date_trunc('year', age(birthdate + interval '20 days'))
I have simply created this year date from original birth date.
( DATE_PART('month', birth_date) || '/' || DATE_PART('day', birth_date) || '/' || DATE_PART('year', now()))::date between :start_date and :end_date
I hope this help.