I need create select for all rows it are older than 15 minutes at the moment.
SELECT last_answer_date FROM messages WHERE last_answer_date > NOW() - INTERVAL '15 minutes';
When I start this select now in 16:51:00 I get result:
2019-01-17 16:25:00
In other words I mean:
Give me all rows where last_answer_date > 16:51:00 - 15 minutes (because now 16:51:00)
Give me all rows `where last_answer_date > 16:36:00 (because now 16:51:00 - 15 minutes = 16:36:00)
And I get 16:25:00 but 16:25:00 < 16:36:00
EDIT: When I change > to < I get 2019-01-16 17:50:27
EDIT2: Example:
SELECT insert_date FROM smev_messages WHERE insert_date < NOW() - INTERVAL '15 minutes';
now = 17:16
change to SELECT insert_date FROM smev_messages WHERE insert_date > NOW() - INTERVAL '15 minutes';
17:17
I think it might be a problem with your timezone.
You can check it with show timezone;
Or simply go with select now() and see if it matches your expectations.
If you have a big table with a lot of data you will get some performance problems because when you call
NOW() - INTERVAL '15 minutes' internally postgress need convert your interval to a date
Postgress Interval
I think a better way to-do that you should do something like that to improve performance, because all dates are long values and you should compare it like long values.
-- 15 minutes in millis = 900000
-- 15 minutes in secods = 900
-- Retrive all data inserted at latest 15 minutes
SELECT last_answer_date FROM messages WHERE (NOW() - last_answer_date) < 900;
-- Retrive all data inserted more than 15 minutes
SELECT last_answer_date FROM messages WHERE (NOW() - last_answer_date) > 900;
Related
how can I select in MariaDB between two dates (in this case between two minutes)? I mean I want to select between from now() +5 minutes and now() + 30 minutes.
I tried with this query but no luck.
SELECT req_id FROM info WHERE date(sent_date) BETWEEN (NOW() - INTERVAL 5 MINUTE) AND date(sent_date) < (NOW() - INTERVAL 30 MINUTE)
Thank you so much for helping.
BTW, I tried to search answer to my question in stackoverflow but I don't found.
The syntax of your WHERE clause is off. Use this version:
SELECT req_id
FROM info
WHERE sent_date BETWEEN NOW() - INTERVAL 5 MINUTE AND NOW() - INTERVAL 30 MINUTE;
This is used in a database package as a delay to pass data. The delay is 2 minutes so I need to only retrieve records if they've been in the database for 2 minutes or more.
This is what I have:
((SYSDATE - trunc(last_updated))*24*60) > l_delay_mins;
l_delay_mins = 2 minutes in this case.
However, the trunc cuts off the time and defaults to midnight, when the conversion is done it gives me the fraction of the day and then multiplies 24*60 which is always larger than 2, so the records aren't being delayed and are sending as soon as they arrive.
Use INTERVAL:
where last_updated < systimestamp - (l_delay_mins * interval '1' minute);
Here is the same thing without INTERVAL but with a minute being a fraction of the day (kind of what you tried):
where last_updated < systimestamp - (l_delay_mins / 24 / 60)
A minor amendment to the above answer
Use INTERVAL:
where last_updated <= systimestamp - (l_delay_mins * interval '1' minute);
Say I want to find orders made recently. I am trying this statement:
SELECT * FROM orders WHERE time < now() - interval '30 second';
This doe not work (It does not select any row.) although the following works:
SELECT * FROM orders WHERE time < now();
Do I need to use a fixed time variable? Like:
SELECT * FROM orders WHERE time < '2018-07-01 12:00:00' - interval '30 second';
I am guessing that I should not use now() in statements because it can be changing during operations ...
I believe you have the comparison in the wrong direction:
SELECT *
FROM orders
WHERE time > now() - interval '30 second';
This returns values in the last 30 seconds.
This assumes that time is of an appropriate date type for the comparison.
I have a table(pkg_date) in redshift. I want to fetch some data for every date for the last 3 months.
Here is my query
select * from pkg_data where scan_date < current_date;
How can I use current_date as a variable in the query itself and run this query for every date from April 1.
I have set a cron job which will run in every hour. In every hour it should run with different current_date
SELECT *
FROM pkg_data
WHERE scan_date > CURRENT_DATE - INTERVAL '3 months'
Be careful — Redshift works in UTC, so the CURRENT_DATE might suffer from timezone effects and be +/- what you expect sometimes.
SELECT
CURRENT_DATE,
(CURRENT_DATE - INTERVAL '3 months')::date
Returns:
2018-06-21 2018-03-21
Also be careful with strange lengths of months!
SELECT DATE '2018-05-31' - INTERVAL '3 months'
returns:
2018-02-28 00:00:00
Notice that it gave the last day of the month (31st vs 28th).
By the way, you can use DATE '2018-05-31' or '2018-05-31'::DATE, and also INTERVAL '3 months' or '3 months'::INTERVAL to convert types.
Use dateadd() for getting date 3 moth old day and GETDATE() for get current date.
ie code will look like.
select * from pkg_data where scan_date < dateadd(month,-3,GETDATE());
for cron refer How to execute scheduled SQL script on Amazon Redshift?
If I write:
SELECT *
FROM table
WHERE date >= NOW - INTERVAL '5 MINTUE';
I will get all the data from the last 5 minutes, but the first and last minute won't be full minutes, they'll likely be partial minutes. Meaning if "NOW()" is 4:30:24, then NOW() - INTERVAL '5 MINUTE' will get me from 4:25:24 to 4:30:24. Minute 25 is partial and only contains 36 seconds, same with minute 30 which only contains 24 seconds.
How would I go about getting the last full 5 minutes? I considered removing the first and last minute or min/max, but that idea became a challenge when I consider minute [58, 59, 60, 01, 02]. In this case min/max doesn't account for the cycle back to 0 after minute 60.
Any ideas would be helpful.
You can use date_trunc():
SELECT *
FROM table
WHERE date >= date_trunc('minute', now()) - interval '5 minute' and
date < date_trunc('minute', now())
Try something like this
SELECT *
FROM table
WHERE date >= DateADD(mi, -5, Current_TimeStamp)