In my code using SQL Server, I am comparing data between two months where I have the exact dates identified. I am trying to find if the value in a certain column changes in a bunch of different scenarios. That part works, but what I'd like to do is make it so that I don't have to always go back to change the date each time I wanted to get the results I'm looking for. Is this possible?
My thought was that adding a WITH clause, but it is giving me an aggregation error. Is there anyway I can go about making this date problem simpler? Thanks in advance
EDIT
Ok I'd like to clarify. In my WITH statement, I have:
select distinct
d.Date
from Database d
Which returns:
+------+-------------+
| | Date |
+------+-------------|
| 1 | 01-06-2017 |
| 2 | 01-13-2017 |
| 3 | 01-20-2017 |
| 4 | 01-27-2017 |
| 5 | 02-03-2017 |
| 6 | 02-10-2017 |
| 7 | 02-17-2017 |
| 8 | 02-24-2017 |
| 9 | ........ |
+------+-------------+
If I select this statement and execute, it will return just the dates from my table as shown above. What I'd like to do is be able to have sql that will pull from these date values and compare the last date value from one month to the last date value of the next month. In essence, it should compare the values from date 8 to values from date 4, but it should be dynamic enough that it can do the same for any two dates without much tinkering.
If I didn't misunderstand your request, it seems you need a numbers table, also known as a tally table, or in this case a calendar table.
Recommended post: https://dba.stackexchange.com/questions/11506/why-are-numbers-tables-invaluable
Basically, you create a table and populate it with numbers of year's week o start and end dates. Then join your main query to this table.
+------+-----------+----------+
| week | startDate | endDate |
+------+-----------+----------+
| 1 | 20170101 | 20170107 |
| 2 | 20170108 | 20170114 |
+------+-----------+----------+
Select b.week, max(a.data) from yourTable a
inner join calendarTable b
on a.Date between b.startDate and b.endDate
group by b.week
dynamic dates to filter by BETWEEN
select dateadd(m,-1,dateadd(day,-(datepart(day,cast(getdate() as date))-1),cast(getdate() as date))) -- 1st date of last month
select dateadd(day,-datepart(day,cast(getdate() as date)),cast(getdate() as date)) -- last date of last month
select dateadd(day,-(datepart(day,cast(getdate() as date))-1),cast(getdate() as date)) -- 1st date of current month
select dateadd(day,-datepart(day,dateadd(m,1,cast(getdate() as date))),dateadd(m,1,cast(getdate() as date))) -- last date of the month
Related
You may be aware of rolling the results of an aggregate over a specific number of preceding rows. I.e.: how many hot dogs did I eat over the last 7 days
SELECT HotDogCount,
DateKey,
SUM(HotDogCount) OVER (ORDER BY DateKey ROWS 6 PRECEDING) AS HotDogsLast7Days
FROM dbo.HotDogConsumption
Results:
+-------------+------------+------------------+
| HotDogCount | DateKey | HotDogsLast7Days |
+-------------+------------+------------------+
| 3 | 09/21/2020 | 3 |
| 2 | 9/22/2020 | 5 |
| 1 | 09/23/2020 | 6 |
| 1 | 09/24/2020 | 7 |
| 1 | 09/25/2020 | 8 |
| 4 | 09/26/2020 | 12 |
| 1 | 09/27/2020 | 13 |
| 3 | 09/28/2020 | 13 |
| 2 | 09/29/2020 | 13 |
| 1 | 09/30/2020 | 13 |
+-------------+------------+------------------+
Now, the problem I am having is when there are gaps in the dates. So, basically, one day my intestines and circulatory system are screaming at me: "What the heck are you doing, you're going to kill us all!!!" So, I decide to give my body a break for a day and now there is no record for that day. When I use the "ROWS 6 PRECEDING" method, I will now be reaching back 8 days, rather than 7, because one day was missed.
So, the question is, do any of you know how I could use the OVER clause to truly use a date value (something like "DATEADD(day,-7,DateKey)") to determine how many previous rows should be summed up for a true 7 day rolling sum, regardless of whether I only ate hot dogs on one day or on all 7 days?
Side note, to have a record of 0 for the days I didn't eat any hotdogs is not an option. I understand that I could use an array of dates and left join to it and do a
CASE WHEN Datekey IS NULL THEN 0 END
type of deal, but I would like to find out if there is a different way where the rows preceding value can somehow be determined dynamically based on the date.
Window functions are the right approach in theory. But to look back at the 7 preceding days (not rows), we need a range frame specification - which, unfornately, SQL Server does not support.
I am going to recommend a subquery, or a lateral join:
select hdc.*, hdc1.*
from dbo.HotDogConsumption hdc
cross apply (
select coalesce(sum(HotDogCount), 0) HotDogsLast7Days
from dbo.HotDogConsumption hdc1
where hdc1.datekey >= dateadd(day, -7, hdc.datekey)
and hdc1.datekey < hdc.datekey
) hdc1
You might want to adjust the conditions in the where clause of the subquery to the precise frame that you want. The above code computes over the last 7 days, not including today. Something equivalent to your current attempt would be like:
where hdc1.datekey >= dateadd(day, -6, hdc.datekey)
and hdc1.datekey <= hdc.datekey
I'm kind of old school, but this is how I'd go about it:
SELECT
HDC1.HotDogCount
,HDC1.DateKey
,( SELECT SUM( HDC2.HotDogCount )
FROM HotDogConsumption HDC2
WHERE HDC2.DateKey BETWEEN DATEADD( DD, -7, HDC1.DateKey )
AND HDC1.DateKey ) AS 'HotDogsLast7Days'
FROM
HotDogConsumption HDC1
;
Someone younger might use an OUTER APPLY or something.
My goal is to join a sales program table to a calendar table so that there would be a joined table with the full trailing 52 weeks by day, and then the sales data would be joined to it. The idea would be that there are nulls I could COALESCE after the fact. However, my problem is that I only get results without nulls from my sales data table.
The questions I've consulted so far are:
Join to Calendar Table - 5 Business Days
Joining missing dates from calendar table Which points to
MySQL how to fill missing dates in range?
My Calendar table is all 364 days previous to today (today being day 0). And the sales data has a program field, a store field, and then a start date and an end date for the program.
Here's what I have coded:
SELECT
CAL.DATE,
CAL.DAY,
SALES.ITEM,
SALES.PROGRAM,
SALES.SALE_DT,
SALES.EFF_BGN_DT,
SALES.EFF_END_DT
FROM
CALENDAR_TABLE AS CAL
LEFT JOIN
SALES_TABLE AS SALES
ON CAL.DATE = SALES.SALE_DT
WHERE 1=1
and SALES.ITEM = 1 or SALES.ITEM is null
ORDER BY DATE ASC
What I expected was 365 records with dates where there were nulls and dates where there were filled in records. My query resulted in a few dates with null values but otherwise just the dates where a program exists.
DATE | ITEM | PROGRAM | SALE_DT | PRGM_BGN | PRGM_END |
----------|--------|---------|----------|-----------|-----------|
8/27/2020 | | | | | |
8/26/2020 | | | | | |
8/25/2020 | | | | | |
8/24/2020 | | | | | |
6/7/2020 | 1 | 5 | 6/7/2020 | 2/13/2016 | 6/7/2020 |
6/6/2020 | 1 | 5 | 6/6/2020 | 2/13/2016 | 6/7/2020 |
6/5/2020 | 1 | 5 | 6/5/2020 | 2/13/2016 | 6/7/2020 |
6/4/2020 | 1 | 5 | 6/4/2020 | 2/13/2016 | 6/7/2020 |
Date = Calendar day.
Item = Item number being sold.
Program = Unique numeric ID of program.
Sale_Dt = Field populated if at least one item was sold under this program.
Prgm_bgn = First day when item was eligible to be sold under this program.
Prgm_end = Last day when item was eligible to be sold under this program.
What I would have expected would have been records between June 7 and August 24 which just had the DATE column populated for each day and null values as what happens in the most recent four records.
I'm trying to understand why a calendar table and what I've written are not providing the in-between dates.
EDIT: I've removed the request for feedback to shorten the question as well as an example I don't think added value. But please continue to give feedback as you see necessary.
I'd be more than happy to delete this whole question or have someone else give a better answer, but after staring at the logic in some of the answers in this thread (MySQL how to fill missing dates in range?) long enough, I came up with this:
SELECT
CAL.DATE,
t.* EXCEPT (DATE)
FROM
CALENDER_TABLE AS CAL
LEFT JOIN
(SELECT
CAL.DATE,
CAL.DAY,
SALES.ITEM,
SALES.PROGRAM,
SALES.SALE_DT,
SALES.EFF_BGN_DT,
SALES.EFF_END_DT
FROM
CALENDAR_TABLE AS CAL
LEFT JOIN
SALES_TABLE AS SALES
ON CAL.DATE = SALES.SALE_DT
WHERE 1=1
and SALES.ITEM = 1 or SALES.ITEM is null
ORDER BY DATE ASC) **t**
ON CAL.DATE = t.DATE
From what I can tell, it seems to be what I needed. It allows for the subquery to connect a date to all those records, then just joins on the calendar table again solely on date to allow for those nulls to be created.
Below I have the tables and query which output the below
Table1
EmployeeID | StartDateTimestamp | CohortID | CohortName
---------- | ------------------ | -------- | ----------
1 | 20080101 01:30:00 | 1 | Peanut
1 | 20090204 01:01:00 | 2 | Apple
2 | 20190107 05:52:14 | 1 | Peanut
3 | 20190311 02:35:26 | 2 | Apple
Employee
EmployeeID | HireStartName | StartDateTimestamp2
---------- | ------------- | -------------------
1 | HiredStart | 20080501 01:30:00
1 | DeferredStart | 20090604 01:01:00
2 | HiredStart | 20190115 05:52:14
3 | HiredStart | 20190330 02:35:26
Query
select
t.cohortid,
min(e.startdatetimestamp2) first,
max(e.startdatetimestamp2) last
from table1 t
inner join employee e on e.employeeid = t.employeeid
group by t.cohort_id
Output
ID | FIRST | LAST
1 |20190106 12:00:05 |20180214 03:45:12
2 |20180230 01:45:23 |20180315 01:45:23
My attempt:
SELECT DATE_DIFF(first, last, Day), ID, max(datecolumn1) first, min(datecolumn1) last
Error: Unrecognized name.
How do I enter the reference alias first and last in a Date_Diff?
Do I need to derive a table?
Clarity: Trying to avoid inputting in the dates, since I am looking to find the date diff of both first and last columns for as many rows as there is data.
This answer has been discussed here: Date Difference between consecutive rows
DateDiff has deprecated, and now it is Date_Diff (first, last, day)
Then I tried:
SELECT ID, DATE_DIFF(PARSE_DATE('%y%m%d',t.first), PARSE_DATE('%y%m%d',t.last), DAY) days
FROM table
Failed to parse input string "20180125 01:00:05"
Tried this
SELECT CohortID, date_diff(first,last,day) as days
FROM (select cohortid,min(startdatetimestamp2) first,
max(startdatetimestamp2) last
FROM employee
JOIN table1 on table1.employeeid = employee.employeeid
group by cohortid)
I get days not found on either side of join
Regarding your first question about using aliases in a query, there are some restriction where to use them, specially in the FROM, GROUP BY and ORDER BY statements. I encourage you to have a look here to check these restrictions.
About your main issue, obtaining the date difference between two dates. I would like to point that your timestamp data, in both of your tables, are actually considered as DATETIME format in BigQuery. Therefore, you should use DATETIME builtin functions to get the desired results.
The below query uses the data you provided to obtain the aimed output.
WITH
data AS
(
SELECT
t.cohortid AS ID,
PARSE_DATETIME('%Y%m%d %H:%M:%S', MIN(e.startdatetimestamp2)) AS first,
PARSE_DATETIME('%Y%m%d %H:%M:%S', MAX(e.startdatetimestamp2)) AS last
FROM
`test-proj-261014.sample.table1` t
INNER JOIN
`test-proj-261014.sample.employee` e
ON
e.employeeid = t.employeeid
GROUP BY t.cohortid
)
SELECT
ID,
first,
last,
DATETIME_DIFF(last, first, DAY ) AS diff_days
FROM
data
And the output:
Notice that I created a temp table to format the fields StartDateTimestamp and StartDateTimestamp2, using the PARSE_DATETIME(). Afterwards, I used the DATETIME_DIFF() method to obtain the difference in days between the two fields.
I have a table ORDERS(idOrder, idProduct, Qty, OrderDate) where OrderDate is a varchar column with timestamp values, is it possible to get the Qty of each day, week, month or year ?
The table looks like this :
---------------------------------------
|idOrder | idProduct | Qty | OrderDate|
---------------------------------------
| 1 | 5 | 20 | 1504011790 |
| 2 | 5 | 50 | 1504015790 |
| 3 | 5 | 60 | 1504611790 |
| 4 | 5 | 90 | 1504911790 |
-----------------------------------------
and i want something like this
------------------------------
| idProduct | Qty | OrderDate|
-------------------------------
| 5 | 70 | 08/29/2017|
| 5 | 60 | 09/05/2017|
| 5 | 90 | 09/08/2017|
-------------------------------
looks like you want to do 2 things here: first group by your idProduct and OrderDate
select idProduct, sum(Qty), OrderDate from [yourtable] group by idProduct, OrderDate
This will get you the sums that you want. Next, you want to convert time formats. I assume that your stamps are in Epoch time (number of seconds from Jan 1, 1970) so converting them takes the form:
dateadd(s,[your time field],'19700101')
It also looks like you wanted your dates formatted as mm/dd/yyyy.
convert(NVARCHAR, [date],101) is the format for accomplishing that
Together:
select idProduct, sum(Qty), convert(NVARCHAR,dateadd(s,OrderDate,'19700101'), 101)
from [yourtable]
group by idProduct, OrderDate
Unfortunately, the TSQL TIMESTAMP data type isn't really a date. According to this SO question they're even changing the name because it's such a misnomer. You're much better off creating a DATETIME field with a DEFAULT = GETDATE() to keep an accurate record of when a line was created.
That being said, the most performant way I've seen to track dates down to the day/week/month/quarter/etc. is to use a date dimension table that just lists every date and has fields like WeekOfMonth and DayOfYearand. Once you join your new DateCreated field to it you can get all sorts of information about that date. You can google scripts that will create a date dimension table for you.
Yes its very simple:
TRUNC ( date [, format ] )
Format can be:
TRUNC(TO_DATE('22-AUG-03'), 'YEAR')
Result: '01-JAN-03'
TRUNC(TO_DATE('22-AUG-03'), 'MONTH')
Result: '01-AUG-03'
TRUNC(TO_DATE('22-AUG-03'), 'DDD')
Result: '22-AUG-03'
TRUNC(TO_DATE('22-AUG-03'), 'DAY')
Result: '17-AUG-03'
I am currently trying to accomplish the following:
get the Last Weekstamp for the last 6 Months, the following ilustrates how the end result might look like:
Month | Weekstamp |
2013-12| 2013-52 |
2014-01| 2014-05 |
.... and so on
I have a auxiliary Table, which has all Weeks in it and allows me to connect to a Calender Table, which in turn has all months, meaning i am able to get all weekstamps per Month,
but how do i get all of the Last Week Numbers for the Last 6 Months ?
my idea was a Temporary table of some sor (never used one, am a beginner when it Comes to SQL)
which calculates all of the Weekstamps needing to be filtered out per month, and than gives out only values which i could than use to filter a query which contains all the data i Need.
Anybody have a better idea?
As i said I am just a beginner so i can't really say what the best way would be
Thanks a lot in Advance!
My guess is that your challenge is determining what the last six months are. To do this you can use a tally table (spt_values) and DateDiff to determine when the last six months are.
You can also depending on which DB and version easily do this without a calander or weeks table.
This
WITH rnge
AS (SELECT number
FROM master..spt_values
WHERE type = 'P'
AND number > 0
AND number < 7),
dates
AS (SELECT EOMONTH(Dateadd(m, number * -1, Getdate())) dt
FROM rnge)
SELECT Year(dt) year,
Month(dt) month,
Datepart(wk, dt) week
FROM dates
Produces this output
| YEAR | MONTH | WEEK |
|------|-------|------|
| 2014 | 1 | 5 |
| 2013 | 12 | 53 |
| 2013 | 11 | 48 |
| 2013 | 10 | 44 |
| 2013 | 9 | 40 |
| 2013 | 8 | 35 |
Demo
I'll leave it to you to format the values
This assumes SQL Server 2012 since it uses EOMONTH see Get the last day of the month in SQL for previous versions of SQL Server