I want to query a table to find out a count of objects created by date, day and month in Postgres.
Fetch count for last 30 days
SELECT d.date, count(se.id)
FROM (SELECT to_char(date_trunc('day', (current_date - offs)), 'YYYY-MM-DD') AS date
FROM generate_series(0, 30) AS offs) d LEFT OUTER JOIN
someTable se
ON d.date = to_char(date_trunc('day', se.created_at), 'YYYY-MM-DD')
GROUP BY d.date;
Fetch count by day
select to_char(created_at,'day') as Day,
extract(month from created_at) as Date,
count("id") as "Count"
from someTable
group by 1,2
Fetch count by month
select to_char(created_at,'Mon') as mon,
extract(year from created_at) as yyyy,
count("id") as "Count"
from someTable
group by 1,2
This works fine for me. The problem that I have is, I want the data to be fetched based on different timezones. I have stored the time in UTC. I would be able to run these queries with different timezones.
What is the best way to do it?
Check this answer to get the datetime in Postgres with different timezone.
Fetch count for last 30 days
SELECT d.date, count(se.id)
FROM (SELECT to_char(date_trunc('day', (current_date - offs)), 'YYYY-MM-DD') AS date
FROM generate_series(0, 30) AS offs) d LEFT OUTER JOIN
someTable se
ON d.date = to_char(date_trunc('day', se.created_at::timestamp with time zone at time zone 'EST'), 'YYYY-MM-DD')
GROUP BY d.date;
Fetch count by day
select to_char(created_at::timestamp with time zone at time zone 'EST','day') as Day,
extract(month from created_at) as Date,
count("id") as "Count"
from someTable
group by 1,2
Fetch count by month
select to_char(created_at::timestamp with time zone at time zone 'EST','Mon') as mon,
extract(year from created_at) as yyyy,
count("id") as "Count"
from someTable
group by 1,2
Also refer to this Postgres documentation to learn about timezone with datetime.
Related
Here is a complex query where i need to pass some dates as dynamic to this, As of now i have hardcoded this '2021-08-01' AND '2022-07-31' these 2 dates.
But i have to pass this dates dynamically in such a way that next dates ie, 2022-06 month , thew dates passed will be '2021-07-01' and '2022-06-30' , basically 12 months behind data.
if we take 2022-05 then the passed date should be '2021-06-01' and '2022-05-31'.
How can we achieve this ? Any suggestions or help will be much appreciated.
below is the query for reference
WITH base as
(
SELECT created_at as period ,order_number, TRIM(email) as email ,is_first_order
FROM orders
WHERE created_at::DATE BETWEEN '2021-08-01' AND '2022-07-31'
)
,base_agg as
(
select TO_CHAR(period,'YYYY-MM') as period
,COUNT(DISTINCT email)FILTER(WHERE is_first_order IS TRUE) as new_users
,COUNT(DISTINCT order_number)FILTER(WHERE is_first_order IS FALSE) as returning_orders
FROM base
GROUP BY 1
)
,base_cumulative as
(
SELECT ROW_NUMBER() OVER(ORDER BY PERIOD DESC ) as rno
,period
,new_users
,returning_orders
,sum("new_users")over (order by "period" asc rows between unbounded preceding and current row) as "cumulative_total"
from base_agg
)
SELECT
(SELECT period FROM base_cumulative WHERE rno=1) period
,(SELECT cumulative_total FROM base_cumulative WHERE rno=1) as cumulated_customers
,SUM(returning_orders) as returning_orders
,SUM(returning_orders)/NULLIF((SELECT cumulative_total FROM base_cumulative WHERE rno=1),0) as rate
FROM base_cumulative
You can calculate the end of current month based on NOW() and some logic, the same can be applied with the rest of the calculation
select date_trunc('month', now())::date + interval '1 month - 1 day' end_of_this_month,
date_trunc('month', now())::date + interval '1 month - 1 day'::interval - '1 year'::interval + '1 day'::interval first_day_of_prev_year_month
;
Result
end_of_this_month | first_day_of_prev_year_month
---------------------+------------------------------
2022-08-31 00:00:00 | 2021-09-01 00:00:00
(1 row)
Right now I'm getting an average for each month
SELECT EXTRACT(MONTH FROM date_time) AS month,
EXTRACT(YEAR FROM date_time) AS year,
avg("total")
FROM my_table
GROUP BY EXTRACT(MONTH FROM date_time), EXTRACT(YEAR FROM date_time)
But the SQL query needs to adjust so the total value current month - previous month
Is it possible?
For weekly
SELECT EXTRACT(WEEK FROM date_time) AS week,
EXTRACT(YEAR FROM date_time) AS year,
avg("total")
FROM my_table
GROUP BY EXTRACT(WEEK FROM date_time), EXTRACT(YEAR FROM date_time)
Yes, it's possible:
SELECT t1.month, t2.year, t1.tot - t2.tot FROM
(
SELECT EXTRACT(MONTH FROM date_time) AS month, EXTRACT(YEAR FROM date_time) AS year, avg("total") AS tot
FROM my_table GROUP BY EXTRACT(MONTH FROM date_time), EXTRACT(YEAR FROM date_time)
) t1
join (
SELECT EXTRACT(MONTH FROM date_time) AS month, EXTRACT(YEAR FROM date_time) AS year, avg("total") AS tot
FROM my_table GROUP BY EXTRACT(MONTH FROM date_time), EXTRACT(YEAR FROM date_time)
) t2
on ((t1.year = t2.year) and (t1.month = t2.month + 1)) or
((t1.year = t2.year + 1) and (t1.month = 1) and (t2.month = 12))
I have taken your select and converted it into two subselects, named them as t1 and t2 respectively and joined them by the criteria of left join.
Note that the very first month will not have a pair currently and if you need it nevertheless, then you can use left join and coalesce to make sure that even an unpaired item has a "pair" and a NULL for tot is defaulted to 0.
Note further that you can convert this subquery to a view for better readability.
If I get that correctly, you can first group avg(total) by yer and month, and the use LAG() window function to get previous month value, something like:
with my_table(date_time, total) as (
values
('2022-03-29', 10),
('2022-04-29', 12),
('2022-05-30', 20),
('2022-05-31', 30)
)
,grouped as (
SELECT EXTRACT('MONTH' FROM date_time::timestamp) AS month, EXTRACT('YEAR' FROM date_time::timestamp) AS year, avg("total") AS total
FROM my_table
GROUP BY EXTRACT('MONTH' FROM date_time::timestamp) , EXTRACT('YEAR' FROM date_time::timestamp)
)
SELECT *, LAG(total) OVER(ORDER BY year, month) as prev_month_total
FROM grouped
Select date_trunc('week',dateTime) Date_week, Max(Ranking) Runing_Total_ID
from (select datetime, id , dense_rank () over (order by datetime) as Ranking
from Table1)
group by 1
This query is working for me to give me the running total of total IDs by week. But the week starts on Monday in Postgres by default. Is there any way to change the week start to SUNDAY?
Shift the timestamp back and forth:
Add a day before feeding the timestamp to date_trunc(), then subtract again:
SELECT date_trunc('week', datetime + interval '1 day') - interval '1 day' AS date_week
, max(ranking) AS runing_total_id
FROM (
SELECT datetime, dense_rank() OVER (ORDER BY datetime) AS ranking
FROM table1
) sub
GROUP BY 1;
See:
PostgreSQL custom week number - first week containing Feb 1st
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())
I want to be able to generate groups of row by days, weeks, month or depending on the interval I set
Following this solution, it works when granularity is by month. But trying the interval of 1 week, no records are being returned.
This is the rows on my table
This is the current query I have for per month interval, which works perfectly.
SELECT *
FROM (
SELECT day::date
FROM generate_series(timestamp '2018-09-01'
, timestamp '2018-12-01'
, interval '1 month') day
) d
LEFT JOIN (
SELECT date_trunc('month', created_date)::date AS day
, SUM(escrow_amount) AS profit, sum(total_amount) as revenue
FROM (
select distinct on (order_id) order_id, escrow_amount, total_amount, create_time from order_item
WHERE created_date >= date '2018-09-01'
AND created_date <= date '2018-12-01'
-- AND ... more conditions
) t2 GROUP BY 1
) t USING (day)
ORDER BY day;
Result from this query
And this is the per week interval query. I will reduce the range to two months for brevity.
SELECT *
FROM (
SELECT day::date
FROM generate_series(timestamp '2018-09-01'
, timestamp '2018-11-01'
, interval '1 week') day
) d
LEFT JOIN (
SELECT date_trunc('week', created_date)::date AS day
, SUM(escrow_amount) AS profit, sum(total_amount) as revenue
FROM (
select distinct on (order_id) order_id, escrow_amount, total_amount, create_time from order_item
WHERE created_date >= date '2018-09-01'
AND created_date <= date '2018-11-01'
-- AND ... more conditions
) t2 GROUP BY 1
) t USING (day)
ORDER BY day;
Take note that I have records from October, but the result here doesn't show anything for October dates.
Any idea what I am missing here?
Results from your first query are not truncated to the begin of the week.
date_trunc('2018-09-01'::date, 'week')::date
is equal to
'2018-08-27'::date
so your join using day is not working
'2018-09-01'::date <> '2018-08-27'::date
Your query should look more like that:
SELECT *
FROM (
SELECT day::date
FROM generate_series(date_trunc('week',timestamp '2018-09-01') --series begin trunc
, timestamp '2018-11-01'
, interval '1 week') day
) d
LEFT JOIN (
SELECT date_trunc('week', created_date::date)::date AS day
, SUM(escrow_amount) AS profit, sum(total_amount) as revenue
FROM (
select distinct on (order_id) order_id, escrow_amount, total_amount, create_time from order_item
WHERE created_date::date >= date '2018-09-01'
AND created_date::date <= date '2018-11-01'
-- AND ... more conditions
) t2 GROUP BY 1
) t USING (day)
WHERE day >= '2018-09-01' --to skip days from begining of the week to the begining of the series before trunc
ORDER BY day;