I know of date_part('days', age(release_date)), which will show you days of the age of the release_date col (timestamp). For example, if the release date is 1994-05-30, the date_part calculation would yield 5 days.
However, how can I find out from a countdown perspective, ie, for another release. There are 2 days left till the anniversary of this release hits? Is it just a matter of 365 - date_part('days', age(release_date)), for example? Or is there a better way?
Transpose the release date to the current year and subtract the current date from it. Assuming release_date is an actual date:
SELECT *
, (release_date + (date_trunc('year', LOCALTIMESTAMP)
- date_trunc('year', release_date)))::date
- CURRENT_DATE AS days_till_aniversary
FROM release;
db<>fiddle here
There is a reason for LOCALTIMESTAMP in one spot and CURRENT_DATE in the other. This way, the calculation is done without involving time zones. (Except that either depends on the time zone setting of your session to begin with.) And subtracting dates yields an integer, signifying the difference in days.
Produces negative numbers past anniversaries this year.
Related
I have a below query that I run to extract material movements from the last 7 days.
Purpose is to get the data for the last calender week for certain reports.
select
*
From
redshift
where
posting_date between CURRENT_DATE - 7 and CURRENT_DATE - 1
That means I need to run the query on every Monday to get the data for the former week.
Sometimes I am too busy on Monday or its vacation/bank holiday. In that case I would need to change the query or pull the data via SAP.
Question:
Is there a function for redshift that pulls out the data for the last calender week regardless when I run the query?
I already found following solution
SELECT id FROM table1
WHERE YEARWEEK(date) = YEARWEEK(NOW() - INTERVAL 1 WEEK)
But this doesnt seem to be working for redshift sql
Thanks a lot for your help.
Redshift offers a DATE_TRUNC('week', datestamp) function. Given any datestamp value, either a date or datetime, it gives back the date of the preceding Sunday.
So this might work for you. It filters rows from the Sunday before last, up until but not including, the last Sunday, and so gets a full week.
SELECT id
FROM table1
WHERE date >= DATE_TRUNC('week', NOW()) - INTERVAL 1 WEEK
AND date < DATE_TRUNC('week', NOW())
Pro tip: Every minute you spend learning your DBMS's date/time functions will save you an hour in programming.
I am running the below query to get data recorded in the past 24 hours. I need the same data recorded starting midnight (DATE > 12:00 AM) and also data recorded starting beginning of the month. Not sure if using between will work or if there is better option. Any suggestions.
SELECT COUNT(NUM)
FROM TABLE
WHERE
STATUS = 'CNLD'
AND
TRUNC(TO_DATE('1970-01-01','YYYY-MM-DD') + OPEN_DATE/86400) = trunc(sysdate)
Output (Just need Count). OPEN_DATE Data Type is NUMBER. the output below displays count in last 24 hours. I need the count beginning midnight and another count starting beginning of the month.
The query you've shown will get the count of rows where OPEN_DATE is an 'epoch date' number representing time after midnight this morning*. The condition:
TRUNC(TO_DATE('1970-01-01','YYYY-MM-DD') + OPEN_DATE/86400) = trunc(sysdate)
requires every OPEN_DATE value in your table (or at least all those for CNLD rows) to be converted from a number to an actual date, which is going to be doing a lot more work than necessary, and would stop a standard index against that column being used. It could be rewritten as:
OPEN_DATE >= (trunc(sysdate) - date '1970-01-01') * 86400
which converts midnight this morning to its epoch equivalent, once, and compares all the numbers against that value; using an index if there is one and the optimiser thinks it's appropriate.
To get everything since the start of the month you could just change the default behaviour of trunc(), which is to truncate to the 'DD' element, to truncate to the start of the month instead:
OPEN_DATE >= (trunc(sysdate, 'MM') - date '1970-01-01') * 86400
And the the last 24 hours, subtract a day from the current time instead of truncating it:
OPEN_DATE >= ((sysdate - 1) - date '1970-01-01') * 86400
db<>fiddle with some made-up data to get 72 back for today, more for the last 24 hours, and more still for the whole month.
Based on your current query I'm assuming there won't be any future-dated values, so you don't need to worry about an upper bound for any of these.
*Ignoring leap seconds...
It sounds like you have a column that is of data type TIMESTAMP and you only want to select rows where that TIMESTAMP indicates that it is today's date? And as a related problem, you want to find those that are the current month, based on some system values like CURRENT TIMESTAMP and CURRENT DATE? If so, let's call your column TRANSACTION_TIMESTAMP instead of (reserved word) DATE. Your first query could be:
SELECT COUNT(NUM)
FROM TABLE
WHERE
STATUS = 'CLND'
AND
DATE(TRANSACTION_TIMESTAMP)=CURRENT DATE
The second example of finding all for the current month up to today's date could be:
SELECT COUNT(NUM)
FROM TABLE
WHERE
STATUS = 'CLND'
AND
YEAR(DATE(TRANSACTION_TIMESTAMP)=YEAR(CURRENT DATE) AND
MONTH(DATE(TRANSACTION_TIMESTAMP)=MONTH(CURRENT DATE) AND
DAY(DATE(TRANSACTION_TIMESTAMP)<=DAY(CURRENT DATE)
example, this year is 2020, and the end time of the year islike this
'2020-12-31 23:59:59'
How to select those kind of value?
select endtimeofthisyear()
I understand you want last second of current year. Compute it as 1 s subtracted from first second of next year.
select date_trunc('year', now()) + interval '1 year' - interval '1 second'
Note: currently this is equivalent to concatenating hardcoded string ...23:59:59. If PG handled leap seconds (which AFAIK currently doesn't), it is more likely the leap second would be taken into consideration using expression above.
I can think of no good reason for looking for the last second of a year. If you are filtering by year, then use:
where date >= '2020-01-01' and date < '2021-01-01'
If you are constructing a table with time-tiling -- effective and end dates -- then make the first date inclusive and the second exclusive. Then the next effective date is the previous row's end date -- there is no gap.
You would query a table as:
where <some value> >= eff_dt and <some value> < end_dt
One issue in trying to get the last "moment" is that time is continuous (well, I suppose that is a fundamental question about the universe, but it is how we measure it). If you aim for the last second, you will miss times that occur during the last second, such as 2020-12-31 23:59:59.555.
Since every year ends on the 31.12. 23:59:59, just get the current_date, extract the year and add it.
date_trunc('year', now()) + '-12-31 23:59:59'
Pretty new to SQL and have hit a roadblock.
I have this query, which works fine:
SELECT
(COUNT(*)::float / (current_date - '2017-05-17'::date)) AS "avg_per_day"
FROM "table" tb;
I now want it to include only data from the last month, not all time.
I've tried doing something along the lines of:
SELECT
(COUNT(*)::float / (current_date - (current_date - '1 month' ::date)) AS "avg_per_day"
FROM "table" tb;
The syntax is clearly wrong, but I am not sure what the right answer is. Have googled around and tried various options to no avail.
I can't use a simple AVG because the number I require is an AVG per day for the last month of data. Thus I've done a count of rows divided by the number of days since the first occurrence to get my AVG per day.
I have a column which tells me the date of the occurrence, however there are multiple rows with the same date in the dataset. e.g.
created_at
----------------------------
Monday 27th June 2017 12:00
Monday 27th June 2017 13:00
Tuesday 28th June 2017 12:00
and so on.
I am counting the number of occurrences per day and then need to work out an average from that, for the last month of results only (they date back to May).
The answer depends on the exact definition of "last month" and the exact definition of "average count".
Assuming:
Your column is defined created_at timestamptz NOT NULL
You want the average number of rows per day - days without any rows count as 0.
Cover 30 days exactly, excluding today.
SELECT round(count(*)::numeric / 30, 2) -- simple now with a fixed number of days
FROM tbl
WHERE created_at >= (now()::date - 30)
AND created_at < now()::date -- excl. today
Rounding is optional, but you need numeric instead of float to use round() this way.
Not including the current day ("today"), which is ongoing and may result in a lower, misleading average.
If "last month" is supposed to mean something else, you need to define it exactly. Months have between 28 and 31 days, this can mean various things. And since you obviously operate with timestamp or timestamptz, not date, you also need to be aware of possible implications of the time of day and the current time zone. The cast to date (or the definition of "day" in general) depends on your current timezone setting while operating with timestamptz.
Related:
Ignoring timezones altogether in Rails and PostgreSQL
Select today's (since midnight) timestamps only
Subtract hours from the now() function
I think you just need a where clause:
SELECT
(COUNT(*)::float / (current_date - (current_date - '1 month' ::date)) AS "avg_per_day"
FROM "table" tb
WHERE created_at > (current_date - '1 month' ::date)
I believe Postgresql and other RDBMS has AVG() to calculate average.
SELECT AVG(tb.columnName) AS avg_per_month
FROM someTable tb
WHERE
tb.createdDate >= [start date of month] AND
tb.createdDate <= [end date of month]
Edit: I subtract current date with INTERVAL. I am on mobile phone so I cannot test.
SELECT
(COUNT(*)::float / (current_date - ( current_date - INTERVAL '1 month')) AS "avg_per_day"
FROM "table" tb;
I'm keep track of recurring weekly events in a table using just a DATETIME. I only care about the TIME and the day of the week it falls on.
I need to be able to convert the set DATETIME into the current or upcoming future one.
IE How can I convert a date stored as 2013-02-22 12:00:00 using the current date to the next occurrence? Ie this next Friday at 12:00:00 or 2013-03-01 12:00:00 so that I can then order events by date?
Or I could store the TIME and day of the week separately as a number 0-6.
UPDATE:
From Erwin I got something like:
Event.order("date_trunc('week', now()::timestamp) + (start_at - date_trunc('week', start_at))")
Which seems order them except that the first dates I get are Monday skipping over events I know exist for Sunday which it puts as last.
Your best choice is to store a timestamp or timestamptz (timestamop with time zone). If you have or ever will have to deal with more than one time zone, make that timestamptz and define whether you want to operate with local time or UTC or whatever. More details in this related answer:
Ignoring timezones altogether in Rails and PostgreSQL
Demo how to transpose a timestamp into the current week efficiently (same day of week and time). Assuming timestamp here:
SELECT date_trunc('week', now()::timestamp) + (t - date_trunc('week', t))
FROM (SELECT '2013-02-15 12:00:00'::timestamp AS t) x;
The trick is to compute the interval between the start of the corresponding week and the given timestamp and add that to the start of the current week with the help of date_trunc().
The ISO week starts with Monday, putting Sunday last.
Or, to just add a week to a given timestamp:
SELECT t + interval '1 week';
If You just want to ORDER BY, you only need the interval:
ORDER BY (t - date_trunc('week', t))
If you want to put Sunday first (shifting days):
ORDER BY ((t + interval '1d') - date_trunc('week', (t + interval '1d'))
Or simpler:
ORDER BY EXTRACT(dow FROM t), t::time
Quoting the manual on EXTRACT():
dow
The day of the week as Sunday(0) to Saturday(6)
isodow
The day of the week as Monday(1) to Sunday(7)
Answer to question in comment
I'm only interested in ordering them relative to the current date. Ie
if it's tuesday, I want tuesday first, monday last.
Wrapping at midnight of "today":
ORDER BY (EXTRACT(dow FROM t)::int + 7 - EXTRACT(dow FROM now())::int) % 7
,t::time
Using the modulo operator % to shift the day according to "today".
Using dowinstead of isodow, because starting with 0 makes % simpler.
Keep using the datetime. It's simple and gives you flexibility. You can use the extract function to get your time of day and day of week results. This page will help you. http://www.postgresql.org/docs/9.3/static/functions-datetime.html