I'm working on a booking platform which has several different rates. These rates are determined by the time of day, day of week, and day of year. Here are some examples of the interval types involved:
Monday to Friday, 9am to 5pm
Saturday and Sunday, 12am to 9am
Saturday and Sunday, 9am to 5pm
Saturday and Sunday, 5pm to 12am
December 23rd & 24th, anytime
December 26th & 27th, anytime
What is the best way to represent this, such that it's possible to query for the different effective rates on any given day?
At the moment, the way I've done is using two array type columns, days_of_week[] and hours_of_day[], populating them with the days/hours each rate applies. To account for special cases like December, I also have fields valid_from and invalid_after, however this requires a new entry for each year.
I've had a look at the datetime functions for intervals and such here but haven't seen anything that looks like it could solve this.
why not just listing them in where clause? eg for first sample:
t=# select now(),extract('dow' from now()) between 1 and 5 and now()::time between '09:00' and '17:00';
now | ?column?
-------------------------------+----------
2017-11-27 16:56:01.544642+00 | t
so you take (extract('dow' from now()) between 1 and 5 and now()::time between '09:00' and '17:00') to brackets and add same brackets over OR...
You can addthem all to a function with timestamptz as argument and return true of false to use in where clause
Related
I am trying to query this data set of hourly price date. The dataset defined daily prices at 12am - 12am UTC time, I am trying to define the days at 4pm - 4pm UTC time. Therefore I need to get the high and the low prices for each day between ex: '2021-12-15 16:00:00' and '2021-12-16 15:00:00' as that would be the open and close of the trading day.
I have this right now:
SELECT convert(date,dateadd(S, TimeStamp/1000, '1970-01-01')) as 'date'
,symbol
,Max([high]) as 'Max'
,Min([low]) as 'Min'
FROM [Crypto].[tblMessariPriceHistory]
WHERE symbol = 'DOGE'
and dateadd(S, TimeStamp/1000, '1970-01-01') between '2021-12-15 16:00:00' and '2021-12-16 15:00:00'
Group By convert(date,dateadd(S, TimeStamp/1000, '1970-01-01')),symbol
But it results like this:
date
symbol
Max
Min
2021-12-15
DOGE
0.175059052503167
0.170510833636204
2021-12-16
DOGE
0.180266282681554
0.177596458601872
I could just group by Symbol but I want to be able to do this over multiple days, and that wouldn't work.
Any ideas on how to define a select date range as a group or table over multiple days?
If you think about it, subtracting 16 h off every time would slide the time back to some time within the "starting day"
Monday 16:00 becomes midnight Monday
Monday 23:59 becomes 7:59 Monday
Tuesday 00:00 becomes 8:00 Monday
Tuesday 15:59 becomes 23:59 Monday
Tuesday 16:00 becomes midnight Tuesday
Anyway, once you've slid your time backwards 16h, you can just chop the time part off by dividing the unix time stamp by the number of milliseconds in a day and all the trades between Monday 16:00 and Tuesday 15:59:59.999 will go down as "Monday". If it were a DateTime we could cast it to a Date to achieve the same thing. It's handy to find ways of treating datetimes as decimal numbers where the integral is the date and the fractional is the time because chopping it to an int discards the time and allows daily aggregating. If you wanted hourly aggregating, adjusting the number so it represents the number of hours and fractions of an hour (divide by 3600000, the number of milliseconds in an hour) helps to the same end
--take off 16h then truncate to number of days since epoch
SELECT
(timestamp-57600000)/86400000 as timestamp,
symbol,
min(low) as minlow,
max(high) as maxhigh
FROM trades
GROUP BY (timestamp-57600000)/86400000 as timestamp, symbol
How to find the products expiring within the weekend of the current week?
Say we have Products table including (id, name, production_date, shelf_age)
Example:
Say today is 27/11/2020
“Product X” production_date is 8/11/2020 and its shelf_age is 20 days so its expiry is 28/11/2020 which is a weekend day of this week.
“Product Y” production_date is 7/11/2020 and its shelf_age is 20 days so its expiry is 27/11/2020 which is a working day of this week.
Product X need to be included in the result but Y should be excluded.
Something like this should work i think:
SELECT * FROM Products
WHERE
DATENAME(weekday,DATEADD(d,shelf_age,production_date) IN ('Saturday', 'Sunday')
AND DATEDIFF(d,DATEADD(d,shelf_age,production_date),GETDATE()) < 7
AND DATEDIFF(d,DATEADD(d,shelf_age,production_date),GETDATE()) >= 0
As you can see you can use DATENAME() function to get the name of the day to filter weekdays.
Might be some polishing needed as next clause i have here is <7 which means that if you run a query on Sunday or Saturday it will give you next Sunday and Saturday, but you can play with that.
I am using postgres and wondering how I should store schedule time blocks in a way that allows me to do the following:
If I have a schedule with 3 time blocks:
Monday 8am to 12pm
Monday 10am to 4pm
Thursday 8am to 12pm
And I am trying to find all schedules between Monday and Wednesday that start at 8am.
I am storing the time_blocks as array, and I am not sure how to query them.
I suggest three columns:
dow - Day of the week as integer or string. Either would work, integer is best for storage and performance. (0 - 6; Sunday is 0)
from - time type, time of day
to - time type, time of day
Then you can select this way:
SELECT
*
FROM
"schedule"
WHERE
-- Mon, Tue, Wed
"dow" IN (1,2,3) AND
'08:00:00'::time = "from"
You could search for 8am or earlier this way:
'08:00:00'::time BETWEEN "from" AND "to"
I would like to query data, which is between some week days, as follows:
Last Saturday
The Sunday before it
The Saturday before that queried Sunday on 2.
The Sunday before that queried Saturday on 3.
The query would run automatically every Monday, so I would like to set a dynamic condition for it, so that it automatically picks that days, without depending on any day it will run on in the future.
So for example if today is Monday 01/08/2018:
would be 01/06/2018
would be 12/31/2017
would be 12/30/2017
would be 12/24/2017
I would like to set that conditions in the WHERE clause. For now I am querying it this way, with constant dates for example for last week data:
SELECT *
FROM thisTable
WHERE Date(operation_date) BETWEEN '2018-06-10' AND '2018-06-16'
DBMS: Amazon Redshift
The DATE_TRUNC Function is your friend. It truncates to a Monday.
SELECT
CURRENT_DATE AS today,
DATE_TRUNC('week', CURRENT_DATE) as most_recent_monday,
DATE_TRUNC('week', CURRENT_DATE) - 2 AS most_recent_saturday,
DATE_TRUNC('week', CURRENT_DATE) - 8 AS sunday_before_most_recent_saturday
Returns:
2018-06-21 | 2018-06-18 00:00:00 | 2018-06-16 00:00:00 | 2018-06-10 00:00:00
Note that it treats the date as midnight at the beginning of the day. So, you don't really want to query Sunday to Saturday. You actually want to query Sunday to Sunday (which really means midnight at the start of Sunday to midnight at the start of the next Sunday). This assumes your source date is a timestamp.
If your source date is purely a date, then you would want to use Sunday to Saturday.
If you want to query everything from "last week" (if your definition is Sunday to Sunday), and assuming a timestamp, use:
SELECT *
FROM thisTable
WHERE operation_date BETWEEN
-- Most recent Monday minus 8 days = Two Sundays ago
DATE_TRUNC('week', CURRENT_DATE) - 8 AND
-- Most recent Monday minus 1 day = Most recent Sunday
DATE_TRUNC('week', CURRENT_DATE) - 1
(Well, unless you're on a Sunday already, but that's your problem!)
If the date is a date, you'd have to adjust it a bit.
last Sat: date_trunc('week',getdate())-interval '2 day'
prev Sat: date_trunc('week',getdate())-interval '9 day'
this is for Monday-based week
I have two current SQL queries that I currently use to compare GM% from previous year vs. GM% this year. This is a daily report that I run every morning. The date arithmetic is not very solid and I am trying to find an alternative. Previously I thought that the report would only be for Monday forward, and not including the current day (ie if ran on Tuesday, it would only pull Monday. If ran on Monday it would not pull anything.) Recently that has changed to where when the report is ran on Monday, they want to see Friday-Sunday. What I am considering is setting it to pull the previous 5 day, not including the current day. (Ran on Monday would pull Thur, Fri, Sat, Sun.) The problem is that it has to be a day this year vs same day last year comparison. Anyone who;s tried this knows that it is not easy to get this. Here is my current code for the date arithmetic. I am at a loss guys, I could use some help.
Where DB1.TB1.CLM1>=Current Date-364 days - (DAYOFWEEK(CURRENT DATE) - 2) DAYS
And DB1.TB1.CLM1< Current Date- 364 days
If I hear you right, on Tuesday you would pull stats for Monday. Wed, you pull stats for Mon-Tues. Friday, you pull Mon-Thurs. And for all of these, you need the equivalent day prior year.
The trick is that now on Monday, you need to pull the previous weekend, i.e. Thu-Sun.
You have not defined what to do on Sunday, so I'm leaving that case out.
Try this WHERE statement:
where
( -- do this after Monday
dayofweek(current date) > 2 and
DB1.TB1.CLM1 between ((current date - 364 days) - (dayofweek(current date) - 2) days) and (current_date - 365 days)
)
or
( -- do this on Monday
dayofweek(current date) = 2 and
DB1.TB1.CLM1 between (current date - 368 days) and (current date - 365 days)
)