What I am trying to do is to select a specific month and a specific day from a timestamp. What I have tried is this:
SELECT t FROM test WHERE t BETWEEN '2015-08-01 00:00:00' AND '2015-08-01 23:59:59';
with 8 being the specifc month and 1 being the specific day but this doesn't return anything.
Another thing I would like to do is to choose a specific day of every month of the year what I have tried that I know is wrong but I am not sure how else to do it is:
SELECT t FROM test WHERE t BETWEEN '2015-01-12 00:00:00' AND '2015-24-12 23:59:59';
I can see why this wouldn't work as I take every timestamp from the day in the first month to the same day in the last month, but how can I do it?
edit: I found why it wasn't working for the first example the variable i had for day contained a number so when it was lower than 10 it only said # and not 0#
You could just use a LIKE clause for this. Also your between won't work for edge cases if you have milliseconds after :59.
WHERE t LIKE '2015-08-01 %'
and:
WHERE t LIKE '2015-%-12 %'
Also, regarding optimization, timestamp or similar has text affinity (even though the docs seem to allude to it being numeric). It should allow for like optimization if you have an index, but using ranges will likely be better if you can manage it. I would check the query plans.
Related
I need to round up a month-date based on certain parameters. For example: If I have a parameter where if a day in a given month is between the 6th and the 4th of the next month, I need my query to return the next months date. Is there a way to round up the month given these parameters without hard coding case whens for every single month ever?
SELECT case when date_trunc('day',li.created_at between '2019-03-06 00:00:00' and '2019-04-06 00:00:00' then '2019-04-01' end)
FROM line_items li
If you want the beginning of the month, but offset by 4 days, you can use date_trunc() and subtract some number of days (or add some number of days). You seem to want something like this:
select dateadd(month, 1, date_trunc('month', li.created_at - interval '4 day'))
Another approach is to create a canonical "dates" table that precomputes the mapping from a given date to a new date using your rounding scheme. The mapping could be done outside of redshift in a script and the table loaded in (or within redshift using a user defined function).
I'm currently strugeling to get something done.
I needed only the rows where the date is between a certain date and month.
Example show only the rows where the date is between 01/05 (DD/MM) and 08/07 (DD/MM) the date can be found in the table tasks within the field information.
The year can't make any sense, but the results may only between those two dates in that year.
I've tried:
BETWEEN (TO_DATE ('01/05','DD/MM') AND (TO_DATE('08/07', 'DD/MM')
EXTRACT (DD/MM) from information.
none of those are working for me, I hope that someone of you can help me to figure this out!.
Thanks!
You seem to want to disregard the year. If so, then I would recommend:
TO_CHAR(datecol, 'MM/DD') BETWEEN '05/01' AND '07/08'
In order for BETWEEN to work in this case, you need the format in the order of MM-DD.
If you want this for a particular year, then use direct date comparisons:
datecol >= DATE '2018-05-01' AND
datecol < DATE '2018-07-09' -- note this is one day later
Oracle dates have a time component, so you need to be careful when making comparisons.
In one of my SQL queries, I am using
[... and z.READ_TIMESTAMP > TIMESTAMP_TO_EPOCH(TRUNC(SYSDATE-3)]
If I want the date to be exactly 5/31/2017, will I use 'SYSDATE' (date-n) function or some other expression? or how can a modify my query for 5/31/2017
If you want the date to be exactly 5/31/2017 then use TO_DATE() or TO_TIMESTAMP() depending on which data type you need (date or timestamp). As you are using SYSDATE already the the date data type should work.
-- e.g.
select
to_date('5/31/2017','mm/dd/yyyy')
, to_timestamp('5/31/2017','mm/dd/yyyy')
from dual
...
and z.READ_TIMESTAMP > TIMESTAMP_TO_EPOCH(to_date('5/31/2017','mm/dd/yyyy'))
HOWEVER
I suspect you may want more than just a way to establish a fixed date. For example are you asking for "how do I get that last day of the previous month?" which perhaps can be satisfied by using >= and the first day of current month like this:
...
and z.READ_TIMESTAMP >= TIMESTAMP_TO_EPOCH(trunc(sysdate,'MM'))
or if it really is the last day of the previous month can be achieved with a combination of LAST_DAY() and ADD_MONTHS()
and z.READ_TIMESTAMP >
TIMESTAMP_TO_EPOCH( last_day(add_months(trunc(sysdate,'MM'),-1)) )
Without knowing a great deal more about the nature of your data and query purpose please do note that each date you use when "truncated" also has the time set to 00:00:000 - so IF you data contains time within a day other than 00:00:00 then these 2 queries might NOT produce the same result
.... datetimecolumn > to_date('05/31/2017','mm/dd/yyyy') -- "a"
.... datetimecolumn >= to_date('06/01/2017','mm/dd/yyyy') -- "b"
For example "a" the entire 24 hour duration of 05/31/2017 would be included in the results, but for example "b" that same 24 hour duration would be excluded from results. In my experience the last day of any month isn't really the best method for locating date/time based data, instead usually it is the first day of the next month that produces the correct result.
my problem is trying to use a SELECT statement and order the top 10 by a certain column. I managed to compile something after searching through lots of forums, however I need to confirm that the timestamp in one field is within the last week. I have gotten this to execute however i'm not sure whether this is correct as I can't print the value for the where clause:
SELECT itemid, count(itemid)
FROM Rateddate
WHERE TO_CHAR(CURRENT_TIMESTAMP - DATE_RATED) < TO_CHAR(7)
GROUP BY itemid;
TLDR:
TO_CHAR(CURRENT_TIMESTAMP - DATE_RATED) < TO_CHAR(7)
does this make sure the date_rated timestamp is less than a week old?
It would make more sense to say
WHERE date_rated > sysdate - interval '7' day
if you want data from the last 168 hours. You may want
WHERE date_rated > trunc(sysdate) - interval '7' day
if you want data from any point in the day 7 days ago rather than caring about what time of day it is currently.
Wouldn't this work for you:
trunc(CURRENT_TIMESTAMP - DATE_RATED) < 7
This is assuming that DATE_RATED is a date field. If not, you need to convert it first with TO_DATE().
I have a table in a database with one column containing dates and another one containing scores. Basically, what I want to do is grab the best score in a given week.
Weeks can start on any given day (From Friday to Thursday, for instance), and that is defined by the user.
Here is what I have so far:
SELECT MAX(Series), DATE(DATE(Date, 'weekday 0'), '-7 days') dateStartOfWeek FROM SeriesScores
WHERE Season = '2010-2011'
AND dateStartOfWeek = '2010-08-29'
GROUP BY DateStartOfWeek
Where Series is the column containing the scores and Date is the (badly) named actual date.
The problem with this query is that it works for every day except for the day the week is supposed to be starting on.
For example: 2010-08-29 is a Sunday and in this example, I'm trying to find on which date the Sunday of the given week is. My function works for every day of that week except for 2010-08-29 (Sunday) since it tries to find the next day that is a Sunday (itself in this case). To compensate for that, I go back 7 days to get the correct Sunday, which creates the error for the already correct Sunday since this one doesn't need to go back 7 days or else it is one week off.
I figured I could solve this problem easily using Java, but I want to see how it should be done using SQL instead.
My solution (I don't even know if it can be done), would be to check if date and dateStartOfWeek are the same. If they are, don't substract 7 days from the date. If they're not, do as I did in my example. I don't know how to use conditions such as this one in SQL, though, and this is where I need help.
Thanks a lot in advance!
I think you need to use CASE operator - see http://sqlite.awardspace.info/syntax/sqlitepg09.htm
EDIT - try:
SELECT MAX(Series), CASE WHEN STRFTIME ( '%w', Date ) = 0 THEN DATE(Date, 'weekday 0') ELSE DATE(DATE(Date, 'weekday 0'), '-7 days') END AS dateStartOfWeek FROM SeriesScores
WHERE Season = '2010-2011'
AND dateStartOfWeek = '2010-08-29'
GROUP BY DateStartOfWeek
see http://www.sqlite.org/lang_datefunc.html