I have two columns in a table:
id date
1 1/1/18 12:55:00 AM
2 1/2/18 01:34:00 AM
3 1/3/18 02:45:00 AM
How do I count the number of IDs per month if the time is appended into the date column?
The output would be:
Count month
3 1
In ANSI SQL, you would use:
select extract(month from date) as month, count(*)
from t
group by extract(month from date);
I think more databases support a month() function rather than extract(), though.
you have to extract month and count by using group by
select DATE_PART('month', date) as month,count(id) from yourtable
group by DATE_PART('Month', date)
Related
I have table with transactions in Teradata SQL like below:
ID | trans_date
-------------------
123 | 2021-09-15
456 | 2021-10-20
777 | 2021-11-02
890 | 2021-02-14
... | ...
And I need to calculate average number of transactions made by clients in month: 09, 10 and 11, so as a result I need something like below:
Month | Avg_num_trx
--------------------------------------------------------
09 | *average number of transactions per client in month 09*
10 | *average number of transactions per client in month 10*
11 | *average number of transactions per client in month 11*
How can I do taht in Teradata SQL ?
Not as familiar with Teradata, you could probably start by extracting the month from the trans_date, then grouping id and month and adding in count(id). From there you could group month by avg(count_id). Something like this -
WITH extraction AS(
SELECT
ID,
EXTRACT (MONTH FROM trans_date) AS MM
FROM your_table)
,
WITH id_counter AS(
SELECT
ID,
MM,
COUNT(ID) as id_count
FROM extraction
GROUP BY ID, MM)
SELECT
MM,
AVG(id_count) AS Avg_num_trx
FROM id_counter
ORDER BY MM;
The first CTE grabs month from trans_date.
The second CTE groups ID and month with count(ID) - should give you the total actions in that month for that client ID as id_count.
The final table gets the average of id_count grouped by month, which should be the average interactions per client for the period.
If EXTRACT doesn't work for some reason you could also try STRTOK(trans_date, '-', 2).
Other potential methods to replace -
--current
EXTRACT (MONTH FROM trans_date) AS MM
--option 1
STRTOK(trans_date, '-', 2) AS MM
--option 2
LEFT(RIGHT(trans_date, 5),2) AS MM
Above reworked as subqueries - should help with debugging -
SELECT
MM,
AVG(id_count) AS Avg_num_trx
FROM (SELECT
ID,
MM,
COUNT(ID) as id_count
FROM (SELECT
ID,
EXTRACT (MONTH FROM trans_date) AS MM
FROM your_table) AS a
GROUP BY ID, MM) AS b
ORDER BY MM;
This will return the expected answer:
SELECT
Extract (MONTH From trans_date) AS MM,
Cast(Count(*) AS FLOAT) / Count(DISTINCT id)
FROM my_table
GROUP BY MM
Compare to #procopypaster's answer too see which one is more efficient for your data.
I need to get the count of new subscribers each month of the current year.
DB Structure: Subscriber(subscriber_id, create_timestamp, ...)
Expected result:
date | count
-----------+------
2021-01-01 | 3
2021-02-01 | 12
2021-03-01 | 0
2021-04-01 | 8
2021-05-01 | 0
I wrote the following query:
SELECT
DATE_TRUNC('month',create_timestamp)
AS create_timestamp,
COUNT(subscriber_id) AS count
FROM subscriber
GROUP BY DATE_TRUNC('month',create_timestamp);
Which works but does not include months where the count is 0. It's only returning the ones that are existing in the table. Like:
"2021-09-01 00:00:00" 3
"2021-08-01 00:00:00" 9
First subquery is used for retrieving year wise each month row then LEFT JOIN with another subquery which is used to retrieve month wise total_count. COALESCE() is used for replacing NULL value to 0.
-- PostgreSQL (v11)
SELECT t.cdate
, COALESCE(p.total_count, 0) total_count
FROM (select generate_series('2021-01-01'::timestamp, '2021-12-15', '1 month') as cdate) t
LEFT JOIN (SELECT DATE_TRUNC('month',create_timestamp) create_timestamp
, SUM(subscriber_id) total_count
FROM subscriber
GROUP BY DATE_TRUNC('month',create_timestamp)) p
ON t.cdate = p.create_timestamp
Please check from url https://dbfiddle.uk/?rdbms=postgres_11&fiddle=20dcf6c1784ed0d9c5772f2487bcc221
get the count of new subscribers each month of the current year
SELECT month::date, COALESCE(s.count, 0) AS count
FROM generate_series(date_trunc('year', LOCALTIMESTAMP)
, date_trunc('year', LOCALTIMESTAMP) + interval '11 month'
, interval '1 month') m(month)
LEFT JOIN (
SELECT date_trunc('month', create_timestamp) AS month
, count(*) AS count
FROM subscriber
GROUP BY 1
) s USING (month);
db<>fiddle here
That's assuming every row is a "new subscriber". So count(*) is simplest and fastest.
See:
Join a count query on generate_series() and retrieve Null values as '0'
Generating time series between two dates in PostgreSQL
I have a table of names, dates and numeric values. I want to know the total first date entry and the total sum of numeric values for the first 90 days after the first date.
Eg
name
date
value
Joe
2020-10-30
3
Bob
2020-12-23
5
Joe
2021-01-03
7
Joe
2021-05-30
2
I want a query that returns
name
min_date
sum_first_90_days
Joe
2020-10-30
10
Bob
2020-12-23
5
So far I have
SELECT name, min(date) min_date,
sum(value) over (partition by name
order by date
rows between min(date) and dateadd(day,90,min(date))
) as first_90_days_sum
FROM table
but it's not executing. What's a good approach here? How can I set up a window function to use a dynamic date range for each partition?
You can use window functions and aggregation:
select name, sum(value)
from (select t.*,
min(date) over (partition by name) as min_date
from t
) t
where date <= min_date + interval '90 day'
group by name;
I got a problem while trying to count the entries that were created in a month for the last 6 months.
The table looks like this:
A B C D
Year Month Startingdate Identifier
-----------------------------------------
2019 3 2019-03-12 OAM_1903121
2019 2 2019-03-21 OAM_1902211
And the result should look like:
A B C
Year Month Amount of orders
---------------------------------
2019 3 26
2019 2 34
This is what I have so far, but it doesn't get me the proper results:
SELECT year, month, COUNT(Startingdate) as Amount
FROM table
WHERE Startingdate > ((TRUNC(add_months(sysdate,-3) , 'MM'))-1)
GROUP BY year, month
I have not tested it, but it should work:
select year, month, count(Stringdate) as Amount_of_order
from table
where Stringdate between add_months(sysdate, -6) and sysdate
group by year, month;
Let me know.
Try that :
SELECT YEAR(Startingdate) AS [Year], MONTH(Startingdate) AS [Month], COUNT(*) AS Amount
FROM table
WHERE Startingdate > DATEADD(MONTH, -6, GETDATE())
GROUP BY YEAR(Startingdate), MONTH(Startingdate)
ORDER BY YEAR(Startingdate), MONTH(Startingdate) DESC
I think your issue is the filtering. If so, this should handle the most recent six full months:
SELECT year, month, COUNT(*) as num_orders
FROM table
WHERE Startingdate >= TRUNC(add_months(sysdate, -6) , 'MM')
GROUP BY year, month;
I have a table with a date column. I wanted to get the count of months and display them in the order of months. Months should be displayed as 'Jan', 'Feb' etc. If I use to_char function, the order by happens on text. I can use extract(month from dt), but that will also display month in number format. This is part of a report and month should be displayed in 'Mon' format only.
SELECT to_char(dt,'Mon'), COUNT(*) FROM tb GROUP BY to_char(dt,'Mon') ORDER BY to_char(dt,'Mon');
to_char | count
---------+-------
Dec | 1
Jan | 1
Jul | 2
select month, total
from (
select
extract(month from dt) as month_number,
to_char(dt,'mon') as month,
count(*) as total
from tb
group by 1, 2
) s
order by month_number