I am new using SQL and I need to compare current year sales with the same weekday last year.
In the image below for example 06/01/2001 was on a Tuesday so I need to retrieve the same weekday last year with was on 05/01/2020 "Tuesday"
Thanks in advance
Data with columns
If you have data every day, then you can use lag(). The same weekday last year would be 52 weeks ago (at least that is a reasonable definition). So, using lag():
select t.*, lag(total_sales, 52*7) over (order by current_year)
from t;
Related
So I want to make a query to show me if a certain calendar week has all 7 Day.
It would be okay if it just returns the numbers 1-7.
The table that I have contains articles of the 3 month of 2020 but even so the first week just contains Wednesday to Sunday it still counts it as a calendar week.
With that select I would make pl/sql Script to check it and if yes something happens.
This is an example of the Table:
Date Articel_Id
14.10.2020 78
15.10.2020 80
16.10.2020 96
17.10.2020 100
18.10.2020 99
Can I Use to_char() to check if Calendar Week has all 7 Days ?
If yes, how ?
The challenging is actually defining the weeks. If you want to define them using the ISO standard, then aggregate:
select to_char(date, 'IYYYY-IW') as yyyyww,
count(distinct trunc(date)) as num_days
from t
group by to_char(date, 'IYYYY-IW')
order by yyyyww;
This counts the number of days per week. I'm not sure if you want to filter, have a flag, or what the result set should look like. For filtering, using a having clause, such as having count(distinct trunc(date)) = 7.
I am using standard SQL and am trying to add the weekly sum for product usage by week.
Using code below, I was able to add to each row the respective week and year it falls into. How would I go about summing the totals for an item by week and outputting it in columns, say up to the last 8 weeks.
extract(week from Metrics_Date) as week, EXTRACT(YEAR FROM Metrics_Date) AS year
Image is my raw data with the week and year next to an item:
This image is of above raw data being analyzed further(grouping them together). Here is where I would want to add columns, current_week & firstday of week date, and a sum of that weeks totals.
Any help would be appreciated.
You don't need the extract() by the way, you can do truncation DATE_TRUNC(your_date, WEEK) and it will truncate it to the week, usually easier.
Also, because the result of the truncation is a date, you will have the first day of the week already.
The rest I believe you have it figured out already, but just in case:
SELECT DATE_TRUNC(your_date_field, WEEK) AS week, SUM(message_count) AS total_messages FROM your_table GROUP BY 1
What I need is break down the date by month and the week of that month. For example, for '2020-01-06' I want to see January, 1 week, or for '2020-01-13', I want to see January, 2nd week.
Here is the code that wrote:
.....
distinct t1.incidentid
,t1.status as [CW_Staus],
t1.title
,t1.createddatetime
,datename(MM,t1.createddatetime) as Month
,datename(ww,t1.createddatetime) as Week
.....
Now, what I see is this
However, with the start of each month, I want to restart the week count. for '2020-02-01', I want to see Feb, 1week.
What am I missing in the code?
Thank you
You could try taking the day of the month and divide by 7:
SELECT DISTINCT
t1.incidentid,
t1.status AS [CW_Staus],
t1.title,
t1.createddatetime,
DATENAME(MM, t1.createddatetime) AS Month,
1 + ((DATEPART(day, t1.createddatetime)-1) / 7) AS WeekOfMonth
...
Keep in mind that the above logic assumes that you actually want to reset the count of weeks for each month, at the start of each month. More typically, there are ISO standard ways of counting the week in the year. There are edge cases to be considered, as any given year may not have an whole number of weeks.
I'm currently running the following sql statement in JasperReports Server to bring back my data using derived tables.
Select count(createddate) as ModulesCreatedDuringPastWeek,
count(updateddate) as ModulesUpdatedDuringPastWeek,
createddate,
updateddate
from merchendisingmodule
group by merchendisingmodule.createddate, merchendisingmodule.updateddate
However when grouping my data, I am only able to do it in Year, quarter, month and day. However for my report I'm needing the data to be group weeks, and so I was wondering what I will need to add to my code to do this.
DATEADD(D,-DATEPART(weekday,createddate)+1,createddate)
I use this method to prevent issues around the year transitions (week 53 in first days of januari and also in the last days of december, will group days together that are 360 days apart).
I use the first day of the week, instead of week numbers. I can use these dates to group by.
Also this will ensure that every week is 7 days long, instead of the last week of the year being only 3 or 4 days long.
Btw, in this example the first day of the week is sunday.
If your dates include time, use:
CAST(FLOOR(CAST(createddate AS FLOAT)) AS DATETIME)
instead of createddate in the above SYNTAX
Greetings SQL gurus,
I don't know if you can help me, but I will try. I have several large databases grouped by year (each year in a different database). I want to be able to compare values from a particular week from one year to the next. For example, "show me week 17 of 2008 vs. week 17 of 2002."
I have the following definition of weeks that ideally I would use:
Only 52 weeks each year and 7 days a week (that only takes 364 days),
The first day of the first week starts from January 2nd - which means we do not use January 1st data, and
In leap year, the first day of the first week ALSO starts from the January 2nd plus we skip Feb. 29.
Any ideas?
Thanks in advance.
Best to avoid creating a table because then you have to update and maintain it to get your queries to work.
DatePart('ww',[myDate]) will give you the week number. You may run into some issues though deciding which week belongs to which year - for example if Jan 1 2003 is on Wednesday does the week belong as week 52 in 2002 or week 1 in 2003? Your accounting department will have a day of the week that is your end of week (usually Sat). I usually just pick the year that has the most days in it. DatePart will always count the first week as 1 and in the case of the example above the last week as 53. You may not care that much either way. You can create queries for each year
SELECT DatePart('ww',[myDate]) as WeekNumber,myYearTable.* as WeekNumber
FROM myYearTable
and then join the queries to get your data. You'll loose a couple days at the end of the year if one table has 52 weeks and one has 53 (most will show as 53). Or you can do it by your weekending day - this always gives you Saturday which would push a late week into the following year.
(7-Weekday([myDate]))+[myDate]
then
DatePart('ww',(7-Weekday([myDate]))+[myDate])
Hope that helps
To get the week number
'to get the week number in the year
select datepart( week, datefield)
'to get the week number in the month
select (datepart(dd,datefield) -1 ) / 7 + 1
You don't need to complicate things thinking about leap years, etc. Just compare weeks mon to sun
SInce you havea a specifc defintion of when the week starts that is differnt that the standard used by the db, I think a weeks table is the solution to your problem. For each year create a table that defines the dates contained in each week and the week number. Then by joining to that table as well as the relevant other tables, you can ask for just the data for week 17.
Table structure
Date Week
20090102 1
20090103 1
etc.
I needed to create a query that shows BOTH year AND week numbers, like 2014-52. The year shows correct when you use the Datepart() formula to convert week 53 to week 52 in the previous year, but shows the wrong year for the week that was week 1 previously that should be week 52 now. It show that week as 2015-52 instead of 2014-52.
Furthermore, it sorts the data wrong if you only use only the week number, eg:
2014-1,2014-11,2014-2
To overcome this I created the following query to insert a 0 and also to check for days in week 1 that should still fall under week 52.
ActualWeek: IIf(DatePart("ww",[SomeDate],1,3)=52 And DatePart("ww",[SomeDate])=1, DatePart("yyyy",[SomeDate],1,3)-1,DatePart("yyyy",[SomeDate],1,3)) & "-" & IIf(DatePart("ww",[SomeDate],1,3)<10,"0" & DatePart("ww",[SomeDate],1,3),DatePart("ww",[SomeDate],1,3))