Assuming I have the following table in oracle:
id|orderdatetime (date type)|foodtype (string type)
1|2013-12-02T00:26:00 | burger
2|2013-12-02T00:20:00 | fries
...
(assume there are many dates and times)
Assuming someone happened to have a date in mind (i.e. "2010-12-02T00:25:00").
even though there is no database entry with that specific time in there...
is there some way to query the database such that I can get the row that has a date time that is closest to it without being ahead of the date in mind (ideally, it would be less than or equal to)?
(i.e. in this case, the sql query would return the row for "fries" and not "burger" because the time for burger is past the time the user had in mind despite the fact that the time for "burger" is closer.)
select x.* from (select id,orderdatetime,foods from orders
where orderdatetime <= YOURTIME order by orderdatetime desc)x
where rownum =1
Another would be:
select * from orders where orderdatetime = (select max(orderdatetime) from orders
where orderdatetime <= YOURTIME)
Related
I am creating a customer activity by day table, which requires 9 CTEs.
The first table I want to cross join all customer unique IDs with the dates of a calendar table. So there will be multiple rows with the same unique ID for each day.
The problem is making sure the days are consecutive, regardless of the dates in the following CTEs.
This is a shortened example of what it would look like this:
GUID DATE CONDITIONS
1 3/13/2015 [NULL]
1 3/14/2015 Y
1 3/15/2015 [NULL]
....
1 9/2/2020 Y
2 4/15/2015 Y
2 4/16/2015 [NULL]
2 4/17.2015 [NULL]
2 4/18/2015 Y
...
2 9/2/2020 [NULL]
And so on - so that each customers has consecutive dates with their GUID, beginning with the creation date of their account (i.e. 3/13/2015) and ending on the current date.
the create date is on Table 1 with the unique ID, and I'm joining it with a date table.
My problem is that I can't get the query to run with a minimum create date per unique ID. Because if I don't create a minimum start date, the query runs forever (it's trying to create every unique ID for every consecutive date, even before the customer account was created.)
This is the code I have now.
Can anyone tell me if I have made the min. create date right? It's still just timing out when I run the query.
with
cte_carrier_guid (carrier_guid, email, date, carrier_id) as
(
SELECT
guid as carrier_guid
,mc.email
,dt2.date as date
,mc.id as carrier_id
FROM ctms_db_public.msd_carrier mc
CROSS JOIN public.dim_calendar dt2
WHERE dt2.date <= CURRENT_DATE
AND mc.created_at >= dt2.date
GROUP BY guid, mc.id, dt2."date", mc.email
ORDER BY guid, dt2.date asc
)
Select top 10 * from cte_carrier_guid
Here:
dt2.date <= CURRENT_DATE AND mc.created_at >= dt2.date
Since you want dates between the creation date of the user and today, you probably want the inequality condition on the creation date the other way around. I find it easier to follow when we put the lower bound first:
dt2.date >= mc.created_at AND dt2.date <= CURRENT_DATE
Other things about the query:
You want an INNER JOIN in essence, so use that instead of CROSS JOIN ... WHERE; it is clearer
ORDER BY in a cte makes no sense to me
Do you really need GROUP BY? The columns in the SELECT clause are the same as in the GROUP BY, so all this does is remove potential duplicates (but why would there be duplicates?)
You could probably phrase the cte as:
SELECT ...
FROM ctms_db_public.msd_carrier mc
INNER JOIN public.dim_calendar dt2 ON dt2.date >= mc.created_at
WHERE dt2.date <= CURRENT_DATE
I am using postgres and, I recently encountered that the code I am using has too many roundtrips.
What I am doing is basically getting data from a table on a daily basis because I have to look for changes on a daily basis, but the whole function that does this job is called once a month.
An example of my table
Amount
Id | Itemid | Amount | Date
1 | 2 | 50 | 20-5-20
Now this table can be updated to add items at any point in time and I have to see the total amount that is SUM(Amount) every day.
But here's the catch, I have to add interest to the amount of each day at the rate of 5%.
So I can't just once call the function, I have to look at its value every day.
For example if I add an item of 50$ on the 1st of may then the interest on that day is 5/100*50
I add another item on the 5th of may worth 50$ and now the interest on the 5th day is 5/100*50.
But prior to 5th, the interest was on only 50$ so If I just simply use SUM(Amount)*5/100. It is wrong.
Also, another issue is the fact that dates are stored as timestamps and I need to group it by date of the timestamp because if I group it on the basis of timestamp then it will create multiple rows for the same date which I want to avoid while taking the sum.
So if there are two entries on the same date but different hours ideally the query should sum it up as one single date.
Example
Amount Table
Date | Amount
2020-5-5 20:8:8 100
2020-5-5 7:8:8 | 100
Result should be
Amount Table
Date | Amount
2020-5-5 200
My current code.
for i in numberofdaysinthemonth:
amount = amount + session.query(func.sum(Amount.Amount)).filter(Amount.date<current_date).scalar() * 5/100
I want a query that gets all these values according to dates, for example
date | Sum of amount till that date
20-5-20 | 50
20-6-20 | 100
Any ideas about what I should do to avoid a loop that runs 30 times since the function is called once in a month.
I am supposed to get all this data in a table daywise and aggregated as the sum of amount for each day
That is a simple "running total"
select "date",
sum(amount) over (order by "date") as amount_til_date
from the_table
order by "date";
If you need the amount per itemid
select "date",
sum(amount) over (partition by itemid order by "date") as amount_til_date
from the_table
order by "date";
If you also need to calculate the "compound interest rate" up to that day, you can do that as well:
select item_id,
"date",
sum(amount) over (partition by itemid order by "date") as amount_til_date,
sum(amount) over (partition by item_id order by "date") * power(1.05, count(*) over (partition by item_id order by "date")) as compound_interest
from the_table
order by "date";
To get that for a specific month, add a WHERE clause:
where "date" >= date '2020-06-01'
and "date" < date '2020-07-01'
In general to avoid round trips between application and database, application code must be moved from application to database in stored code (stored procedures an stored functions) using a procedural language. This approach is sometimes called "thick database" in commercial databases like Oracle Database.
PostgreSQL default procedural language is pl/pgsql but you can use Java, Perl, Python, Javascript using PostgreSQL extensions that you would need to install in PostgreSQL.
I'm trying to compare data from an Access 2010 database based on a date interval. Example I have items from various purchase orders and I want to maintain the history of these item's delivery to a warehouse. So my purchase order has a request for a quantity of 10 of a material, for example, and it can be partially delivered in many deliveries and I want to know how this delivery varied in a date interval. To fill the date field the criteria used is the following: if the item had an update in the QtyPending field, I copy the current row deactivating it with a booelan field, create a new entry with the current update date updating the QtyPending field, so the active record is the actual state of the item. So I have a table that holds informations about these items like that
PO POItem QtyPending Date Active
4500000123 10 10 01/09/2014 FALSE
4500000123 10 8 05/09/2014 TRUE
4500000122 30 5 03/09/2014 FALSE
4500000122 30 1 04/09/2014 TRUE
With this example, for the first item, it means that from date 01/09 to 04/09 the QtyPending field didn't suffer a variation, meaning that the supplier didn't make any delivery to me, but from 01/09 to 05/08 he delivered me a qty of 2 of a material. For the second one, from date 03/09 to 04/09 the supplier delivered me a qty of 4 of a material. So, if I were to be making a report query from 02/09/2014 to 04/09/2014, the expected output is like this:
PO POItem QtyDelivered
4500000123 10 0
4500000122 30 4
And a report from 31/08/2014 to 10/09/2014, would have this output
PO POItem QtyDelivered
4500000123 10 2
4500000122 30 4
I'm not coming up with a query to make this report. Can anyone help me?
There are many ways of solving this. The easiest one would be to simply make a query of all the necessary records between two dates, loop over them and insert into a temporary table the result. This temporary table can then be the source of your report. A lot of people will scream at you for not using a big query instead but getting the result that you want in the fastest and simplest way should be your priority.
Your problem with your schema is that you don't have the QtyDelivered stored for each record. If you would have it, it would be an easy thing to sum over it in order to get needed result. By not storing this value, you have transformed a simple and fast query into a much harder and slower one because you need to recalculate this value in some way or other and you must do this without forgetting the fact that it's possible to have more than two records.
For calculating this value, you can either use a sub-query to retrieve the value from the previous row or a Left join do to the same. Once you have this value, you can subtract these two to get the needed difference; allowing for the possibility of Null value if there is no previous row. Once you have these values, you can now sum over them to get the final result with a Group By. Notice that in order to perform these calculations, you need to have one or two more levels of subquery. The first query should be something like:
Select PO, POItem, QtyPending, (Select Top 1 QtyPending from MyTable T2 where T1.PO = T2.PO and T2.Date < T1.Date And (T2.Date between #Date1 and #Date2) Order by T2.Date Desc) as QtyPending2 from MyTable T1 Where T1.Date between #Date1 and #Date2) ...
With this as either another subquery or as a View, you can then compute the desired difference by comparing the values of QtyPending and QtyPending2; without forgetting that QtyPendin2 may be Null. The remaining steps are easy to do.
Notice that the above example is for SQL-Server, you might have to change it a little for Access. In any case, you can find here many examples on how to compare two rows under Access. As noted earlier, you can also use a Left Join instead of a subquery to compare your rows.
I came up with this query that solved the problem, it wasn't that simple
SELECT
ItmDtIni.PO
,ItmDtIni.POItem AS [PO Item]
,ROUND(ItmDtIni.QtyPending - ItmDtEnd.QtyPending, 3) AS [Qty Delivered]
,ROUND((ItmDtIni.QtyPending - ItmDtEnd.QtyPending) * ItmDtEnd.Price, 2) AS [Value delivered(US$)]
//Filtering subqueries to bring only the items in the date interval to make a self join
FROM (((SELECT
PO
,POItem
,QtyPending
,MIN(Date) AS MinDate
FROM Item
WHERE Date BETWEEN FORMAT(begin_date, 'dd/mm/yyyy') AND FORMAT(end_date, 'dd/mm/yyyy')
GROUP BY
PO
,POItem
,QtyPending) AS ItmDtIni
//Self join filtering to bring only items in the date interval with the previously filtered table
INNER JOIN (SELECT
PO
,POItem
,QtyPending
,Price
,MAX(Date) AS MaxDate
FROM Item
WHERE Date BETWEEN FORMAT(begin_date, 'dd/mm/yyyy') AND FORMAT(end_date, 'dd/mm/yyyy')
GROUP BY
PO
,POItem
,QtyPending
,Price) AS ItmDtEnd
ON ItmDtIni.PO = ItmDtEnd.PO
AND ItmDtIni.POItem = ItmDtEnd.POItem)
INNER JOIN PO
ON ItmDtEnd.PO = PO.Numero)
WHERE
//Showing only items that had a variation in the date interval
ROUND(ItmDtIni.QtyPending - ItmDtEnd.QtyPending, 3) <> 0
//Anchoring min date in the interval for each item found by the first subquery
AND ItmDtIni.MinDate = (SELECT MIN(Item.Date)
FROM Item
WHERE
ItmDtIni.PO = Item.PO
AND ItmDtIni.POItem = Item.POItem
AND Date BETWEEN FORMAT(begin_date, 'dd/mm/yyyy') AND FORMAT(end_date, 'dd/mm/yyyy'))
//Anchoring max date in the interval for each item found by the second subquery
AND ItmDtEnd.MaxDate = (SELECT MAX(Item.Date)
FROM Item
WHERE
ItmDtEnd.PO = Item.PO
AND ItmDtEnd.POItem = Item.POItem
AND Date BETWEEN FORMAT(begin_date, 'dd/mm/yyyy') AND FORMAT(end_date, 'dd/mm/yyyy'))
I had a difficult time w/ the title, hope this is a little clearer...
I have a table of data (simplified) like so;
Date
Customer
Amount
1/1/2014
1
100.5
4/4/2014
1
122.5
2/1/2014
3
3.25
...but just short of a million records.
I would like to find the x day (let's say 90) period for each customer that has the largest total amount.
To phase the question a little differently, given all the transactions for all customers, for each customer I would like to find the 90 day period that has the largest total amount and what that total amount is in the period.
Trying to advise a brute force approach where I define all the possible ranges (or iterate over all possible ranges on the fly).
Any thoughts on a more elegant solution?
You can use a self-join for this, but the performance may not be so great:
select t.*,
(select sum(t2.amount)
from table t2
where t2.customer = t.customer and
t2.date >= dateadd(day, -90, t.date) and t2.date <= t.date
) as amount90
from table t;
There is a more efficient method in SQL Server 2012.
Here's a psuedo-code ish kind of answer that I think would work. It'd probably be really slow though.
You could have a function that calculates the number of activities provided a start date and number of days,
--function F
#userid, #startdate, #dayCount
SELECT COUNT(*)
FROM TABLE
WHERE
UserID = #userid
and date > #startDate
and date < Dateadd(#startdate, #dayCount)
and then do a max on that function?
select max(f(user, date))
from TableContainingDateRanges
I have a table dbo.X with DateTime column Y which may have hundreds of records.
My Stored Procedure has parameter #CurrentDate, I want to find out the date in the column Y in above table dbo.X which is less than and closest to #CurrentDate.
How to find it?
The where clause will match all rows with date less than #CurrentDate and, since they are ordered descendantly, the TOP 1 will be the closest date to the current date.
SELECT TOP 1 *
FROM x
WHERE x.date < #CurrentDate
ORDER BY x.date DESC
Use DateDiff and order your result by how many days or seconds are between that date and what the Input was
Something like this
select top 1 rowId, dateCol, datediff(second, #CurrentDate, dateCol) as SecondsBetweenDates
from myTable
where dateCol < #currentDate
order by datediff(second, #CurrentDate, dateCol)
I have a better solution for this problem i think.
I will show a few images to support and explain the final solution.
Background
In my solution I have a table of FX Rates. These represent market rates for different currencies. However, our service provider has had a problem with the rate feed and as such some rates have zero values. I want to fill the missing data with rates for that same currency that as closest in time to the missing rate. Basically I want to get the RateId for the nearest non zero rate which I will then substitute. (This is not shown here in my example.)
1) So to start off lets identify the missing rates information:
Query showing my missing rates i.e. have a rate value of zero
2) Next lets identify rates that are not missing.
Query showing rates that are not missing
3) This query is where the magic happens. I have made an assumption here which can be removed but was added to improve the efficiency/performance of the query. The assumption on line 26 is that I expect to find a substitute transaction on the same day as that of the missing / zero transaction.
The magic happens is line 23: The Row_Number function adds an auto number starting at 1 for the shortest time difference between the missing and non missing transaction. The next closest transaction has a rownum of 2 etc.
Please note that in line 25 I must join the currencies so that I do not mismatch the currency types. That is I don't want to substitute a AUD currency with CHF values. I want the closest matching currencies.
Combining the two data sets with a row_number to identify nearest transaction
4) Finally, lets get data where the RowNum is 1
The final query
The query full query is as follows;
; with cte_zero_rates as
(
Select *
from fxrates
where (spot_exp = 0 or spot_exp = 0)
),
cte_non_zero_rates as
(
Select *
from fxrates
where (spot_exp > 0 and spot_exp > 0)
)
,cte_Nearest_Transaction as
(
select z.FXRatesID as Zero_FXRatesID
,z.importDate as Zero_importDate
,z.currency as Zero_Currency
,nz.currency as NonZero_Currency
,nz.FXRatesID as NonZero_FXRatesID
,nz.spot_imp
,nz.importDate as NonZero_importDate
,DATEDIFF(ss, z.importDate, nz.importDate) as TimeDifferece
,ROW_NUMBER() Over(partition by z.FXRatesID order by abs(DATEDIFF(ss, z.importDate, nz.importDate)) asc) as RowNum
from cte_zero_rates z
left join cte_non_zero_rates nz on nz.currency = z.currency
and cast(nz.importDate as date) = cast(z.importDate as date)
--order by z.currency desc, z.importDate desc
)
select n.Zero_FXRatesID
,n.Zero_Currency
,n.Zero_importDate
,n.NonZero_importDate
,DATEDIFF(s, n.NonZero_importDate,n.Zero_importDate) as Delay_In_Seconds
,n.NonZero_Currency
,n.NonZero_FXRatesID
from cte_Nearest_Transaction n
where n.RowNum = 1
and n.NonZero_FXRatesID is not null
order by n.Zero_Currency, n.NonZero_importDate