I have a table with transaction, date and their respective sales value. I need to calculate sum of Sales of all the distinct transactions on all Saturdays between date x and y. Teradata doesn't have a datename, datepart function. How can I do this?
I'm not Teradata expert, I don't even know it but I've found something. It's not a solution it's only suggestion of course, because you tell nothing about your db schema.
Source Dates and Times in Teradata (thru V2R4.1):
Computing the day of the week for a given date is not easy in SQL. If you need a weekday, I recommend that you look it up in the view sys_calendar.calendar (or join to it), thus:
select day_of_week
from sys_calendar.calendar
where calendar_date = date '2003-05-01';
day_of_week
-----------
5 [i.e. Thursday]
Did an inner join as
inner join sys_calendar.calendar as cal on cal.calendar_date=my_table.date where cal.day_of_week=7
Related
I have a "placements" table with the following fields:
id,
name (string),
start_date (date),
end_date (date),
hourly_rate (float)
My goal is to run reports to see billing forecasts based on this placement data, where 8 hours are billed each workday (M-F.) The billing forecasts need to be able to be run weekly or monthly.
For example, a new placement is made for Jan 1st 2021 to Jan 31st 2021 with a hourly_rate of $50 and I am now able to run a report for an arbitrary time period (weekly, monthy, daily) and see the additional billings for that time period.
To do this, I wanted to use the placement data above to generate another set of data in a fact table that would look like this:
id,
placement_id,
date (date) -- or could be a reference to a date dimension table
amount (float) -- placement.hourly_rate x 8 hours
Is there a way to use Postgres to generate these new rows, or is there a better way to accomplish my goal?
You can use generate_series() and a lateral join:
select p.id, d.date, p.hourly_rate * 8 as amount
from placements p
cross join lateral generate_series(start_date, end_date, '1 day') d(date)
I am trying to write an efficient query to get the sum of the previous 7 days worth of values from a relational DB table, and record each total against the final date in the 7 day period (e.g. the 'WeeklyTotals Table' in the example below). For example, in my WeeklyTotals query, I would like the value for February 15th to be 333, since that is the total sum of users from Feb 9th - Feb 15th, and so on:
I have a base query which gets me my previous weeks users for today's date (simplified for the sake of the example):
SELECT Date, Sum("Total Users")
FROM "UserRecords"
WHERE (dateadd(hour, -8, "UserRecords"."Date") BETWEEN
dateadd(hour, -8, sysdate) - INTERVAL '7 DAY' AND dateadd(hour, -8, sysdate);
The problem is, this only get's me the total for today's date. I need a query which will get me this information for the previous seven days.
I know I can make a view for each date (since I only need the previous seven entries) and join them all together, but that seems really inefficient (I'll have to create/update 7 views, and then do all the inner join operations). I am wondering if there's a more efficient way to achieve this.
Provided there are no gaps, you can use a running total with SUM OVER including the six previous rows. Use ROW_NUMBER to exclude the first six records, as their totals don't represent complete weeks.
select log_date, week_total
from
(
select
log_date,
sum(total_users) over (order by log_date rows 6 preceding) as week_total,
row_number() over (order by log_date) as rn
from mytable
where log_date > 0
)
where rn >= 7
order by log_date;
UPDATE: In case there are gaps, it should be
sum(total_users) over (order by log_date range interval '6' day preceding)
but I don't know whether PostgreSQL supports this already. (Moreover the ROW_NUMBER exclusion wouldn't work then and would have to be replaced by something else.)
Here's a a query that self joins to the previous 6 days and sums the value to get the weekly totals:
select u1.date, sum(u2.total_users) as weekly_users
from UserRecords u1
join UserRecords u2
on u1.date - u2.date < 7
and u1.date >= u2.date
group by u1.date
order by u1.date
You can use the SUM over Window function, with the expression using Date Part, of week.
Self joins are much slower than Window functions.
I am looking for a query which gives me the daily playing time. The start (first_date) and end date(last_update) are given as shown in the Table. The following query gives me the sum of playing time on given date. How can I extend it to get a table from first day to last day and plot the query data in it and show 0 on dates when no game is played.
SELECT startTime, SUM(duration) as sum
FROM myTable
WHERE startTime = endTime
GROUP BY startTime
To show date when no one play you will need create a table days with a date field day so you could do a left join. (100 years is only 36500 rows).
Using select Generate days from date range
This use store procedure in MSQL
I will assume if a play pass the midnight a new record begin. So I could simplify my code and remove the time from datetime field
SELECT d.day, SUM(duration) as sum
FROM
days d
left join myTable m
on CONVERT(date, m.starttime) = d.day
GROUP BY d.day
If I understand correctly, you could try:
SELECT SUM(duration) AS duration, date
FROM myTable
WHERE date <= 20140430
AND date => 20140401
GROUP BY date
This would get the total time played for each date between april 1 and april 30
As far as showing 0 for dates not in the table, I don't know.
Also, the table you posted doesn't show a duration column, but the query you posted does, so I went ahead and used it.
please help me with this. using SQL server 2008
I need to find the number of sales done on the current day.
then find the weekday from current date and based on that find the average of the sales on all those particular weekdays in the last month
ex:
select count(sales) from salestable where orderdate= getdate()
where it gives the count of the sales done on the current date
then I need to find out the average of the sales done on the same weekday for ex if today is Sunday find the average of the sales done in the last month on all Sundays in that month.
I recommend that you borrow the data warehousing technique of creating a Calendar table that you pre-populate with 1 row for every date within the range you might need. You can add to it basically any column that is useful - in this case DayOfWeek and MonthID. Then you can eliminate date math entirely and use joins - sort of like this (not complete but points you in the right direction):
select count(salestable.sales) as salescount, a.salesavg
from salestable
join calendar on salestable.orderdate = calendar.calendardate
join (
select monthid, dayofweek, avg(salestable.sales) as salesavg
from salestable
join calendar on salestable.orderdate = calendar.calendardate
group by monthid, dayofweek) as a
on calendar.monthid = a.monthid and calendar.dayofweek = a.dayofweek
where calendar.calendardate = getdate()
You create and populate the calendar table once and reuse it every time you need to do date operations. Once you get used to this technique, you will NEVER go back to date math.
For this kind of queries are Common Table Expressions very usefull. Then you can use DATEPART function to get day of week.
This solution is also untested and intended to just point you in the right direction.
This solution uses a co-related sub-query to get the average sales.
select
order_date,
count(sales) total_sales,
(select avg(sales)
from sales_table
where order_date between dateadd(day,-30,#your_date) and #your_date
and datepart(WEEKDAY,order_date) = datepart(WEEKDAY,#your_date)
) avg_sales_mth
from sales_table
where order_date = #your_date
I have a "workDate" field and a "receivedDate" field in table "tblExceptions." I need to count the number of days beteen the two. workDate always comes first - so, in effect, it's kind of like workDate is "begin date" and receivedDate is "end date". Some exclusions make it tricky to me though:
First, I need to exclude holidays. i do have a table called "tblHolidays", with one field - holidayDate. I have holidays stored up through next year, so maybe I can incorporate that into the query?
Also, most flummoxing is that work dates can never occur on weekends, but received dates can. So, i somehow need to exclude weekends when i'm counting, but allow for a weekend if the received date happens to fall on a saturday or sunday. so, if the work date is June 3rd, 2011, and received date is June 11th, 2011, the count of valid days would be 7, not 9.
Any help on this is much appreciated. Thanks!
Something like this should give you the number of days with the holidays subtracted:
select
days = datediff(day, workDate, receivedDate)
- (select count(*) from tblHolidays where holidayDate >= workDate and holidayDate < receivedDate)
from
tblExceptions
Note that the date functions differ between database systems. This is based on MS SQL Server, so it may need adapting if you are using some other database.
If you have a table full of dates to include (non-weekends, non-holidays, etc.) and you knew when the 'begin' date and the 'end' date is, then you can do something roughly like this:
select count(*) from tblIncludedDates where beginDateValue <= dateField and endDateValue >= dateField
to get the number of valid days between those dates.