I'm looking to create a 3 column VAT_Parameter table with the following columns:
VATID, VATRate, EffectiveDate
However, I can't get my head around how I would identify which vat rate applies to an invoice date.
for example if the table was populated with:
1, 17.5, 1/4/1991
2, 15, 1/1/2009
3, 20, 4/1/2011
Say for example I have an invoice dated 4/5/2010, how would an SQL query select the correct VAT rate for that date?
select top 1 *
from VatRate
where EffectiveDate<=#InvoiceDate
order by EffectiveDate desc
Or, with a table of invoices
select id, invoicedate, rate
from
(
select
inv.id, inv.invoicedate, vatrate.rate, ROW_NUMBER() over (partition by inv.id order by vatrate.effectivedate desc) rn
from inv
inner join vatrate
on inv.invoicedate>=vatrate.effectivedate
) v
where rn = 1
PS. The rules for the rate of VAT to be charged when the rate changes are more complicated than just the invoice date. For example, the date of supply also matters.
I've run into this kind of thing before. There are two choices I can think of:
1. Expand the table to have two dates: EffectiveFrom and EffectiveTo. (You'll have to have a convention about whether each of these is exclusive or inclusive - but that's always a problem when using dates). This raises the problem of validating that the table population, as a whole, makes sense. e.g. that you don't end up with one row with Rate1 effective from 1/1/2000-1/1/2002, and another (overlapping) with Rate2 effective from 30/10/2001-1/1/2003. Or an uncovered gap in time, where no rate applies. Since this sounds like a very slowly-changing table, populated occasionally (by people who know what they're doing?), this could be the best solution. The SQL to get the effective rate would then be simple:
SELECT VATRate FROM VATTable WHERE (EffectiveFrom<=[YourInvoiceDate]) AND (EffectiveTo>=[YourInvoiceDate])
or
2. Use your existing table structure, and use some slightly more complicated SQL to determine the effective rate for an invoice.
Using your existing structure, something like this would work:
SELECT VATTAble.VATRate FROM
VATTable
INNER JOIN
(SELECT Max(EffectiveDate) AS LatestDate FROM VATTable WHERE EffectiveDate<=
YourInvoiceDate) latest
ON VATTable.EffectiveDate=latest.LatestDate
An easier option may just be to denormalise your data structure and store the VAT rate in the invoice table itself.
Related
I am trying to set up a SCD of Type 2 for historical records within my Customer table. Attached is how the Customer table is set up alongside the expected outcome. Note that the Customer table in practice has 2 million distinct Customer IDs. I tried to use the query below, but the Start_Date and End_Date are repeating for each row.
SELECT t.Customer_ID, t.Lifecyle_ID, t.Date As Start_Date,
LEAD(t.Date) OVER (ORDER BY t.Date) AS End_Date
FROM Customer AS t
I think a three step query is likely needed.
Use LEAD and LAG, partitioned by Customer and ordered by date, to peek at the next row's values for both Date and Lifecycle.
Use a CASE statement to emit a value for End Date when the current row's Lifecycle <> the next row's lifecycle (otherwise emit NULL). Now do the same using LAG for the Effective Date.
Group By or Distinct on the output from Step #2.
Hopefully that makes sense. I'll try to post a code example later today, but hopefully that's enough to get you started.
I currently have data in a table related to transactions. Each record has a purchase ID, a Transaction Number, and up to 5 purchases assigned to the transaction. Associated with each purchase there can be up to 10 transactions. For the first transaction of each purchase I need a field that is a string of each unique purchase concatenated. My solution was slow I estimated it would take 40 days to complete. What would be the most effective way to do this?
What you are looking for can be achieved in 2 steps:
Step1: Extracting the first transaction of each purchase
Depending upon your table configuration this can be done in a couple of different ways.
If your transaction IDs are sequential, you can use something like:
select * from table a
inner join
(select purchaseid,min(transactionid) as transactionid
from table group by purchaseid) b
on a.purchaseid-b.purchaseid and a.transactionid=b.transactionid
If there is a date variable driving the transaction sequence, then:
select a.* from
(select *,row_number() over(partition by purchaseid order by date) as rownum from table)a
where a.rownum=1
Step2: Concatenating the Purchase details
This can be done by using the String_agg function if you are using the latest version of SQL server. If not, the following link highlights a couple of different ways you can do this:
Optimal way to concatenate/aggregate strings
Hope this helps.
Dearest Professionals,
I have a table that sometimes has rows created with duplicate Invoice #'s (EMP_ID). In these rows, there separate date (FILE_DATE) and time (FILE_TIME) columns (genius database design there). I need to remove the older rows of any duplicated EMP_ID's in this database, keeping the most recent date (from FILE_DATE) + time (from FILE_TIME).
Both FILE_DATE and FILE_TIME are date/time field in the database. The software we use writes to this table, adding the date of the invoice to the FILE_DATE column, with YYYY-MM-DD 00:00:00.000 (the zeros all hard coded). Then the FILE_TIME field has 1900-01-01 HH:mm:ss.SSS, the 1900-01-01 hard coded. (the time stamp comes from the time the row was written to the database)
So, long story short, I need to marry these two together, to get the DATE portion of FILE_DATE and the time portion of FILE_TIME, to get the most recent (IF duplicates exist of EMP_ID) and delete all duplicated that are not the most recent of the married FILE_DATE & FILE_TIME.
Here is a sample of what a Before & After situation would look like.
BEFORE:
AFTER:
Any and all help would be insanely appreciated.
Using some good old CTE "magic":
WITH CTE AS (
SELECT *,
ROW_NUMBER() OVER (PARTITION BY EMP_ID
ORDER BY FILE_DATE DESC, FILE_TIME DESC) AS RN
FROM YourTable)
DELETE FROM CTE
WHERE RN > 1;
I think this can be accomplished using MAX and GROUP BY:
select B.EMP_ID
, B.File_date
, Max(B.File_Time) as MaxFileTime
, B.DESC_TEXT_1
from Before B
group
by B.EMP_ID
, B.File_date
, B.DESC_TEXT_1
I'm on T-SQL 2014 and try to order products by their price. Now here is the problem: the price is a calculated field. Eg. I have created a function which evaluates a number of pricing rules (maybe about 4 tables with each about 4,000,000 records combined with JOINs to fit to the current login) and returns the users price for the product. While this is OK if I just want to return the price for a limited number of products it is way to slow if I want to sort by this.
I was thinking about having an additional table like UserProductPrice which will get calculated in the background but this will obviously not always have the correct price in it as the rules etc. could change in between the calculation.
Any suggestion on how I could sort by the price would be most appreciated.
You could use the ROW_NUMBER() function and place this into a temp table:
SELECT
Product,
dbo.ufnPrice(Price) as Price,
ROW_NUMBER() OVER (PARTITION BY Product ORDER BY dbo.ufnPrice(Price) DESC) AS Ranking
INTO #Products
FROM dbo.Products
SELECT
Product,
Price,
FROM #Products
WHERE Ranking = 1
DROP TABLE #Products
Should give you what you need.
Unit - hmy, scode, hProperty
InsurancePolicy - hmy, hUnit, dtEffective, sStatus
Select MAX(i2.dtEffective) as maxdate, u.hMy, MAX(i2.hmy) as InsuranceId,
i2.sStatus
from unit u
left join InsurancePolicy i2 on i2.hUnit = u.hMy
and i2.sStatus in ('Active', 'Cancelled', 'Expired')
where u.hProperty = 2
Group By u.hmy, i2.sStatus
order by u.hmy
This query will return values for the Insurance Policy with the latest Effective Date (Max(dtEffective)). I added Max(i2.hmy) so if there was more than one Insurance Policy for the latest Effective Date, it will return the one with the highest ID (i2.hmy) in the database.
Suppose there was a Unit that had 3 Insurance Policies attached with the same latest effective date and all have different sStatus'.
The result would look like this:
maxdate UnitID InsuranceID sStatus
1/23/12 2949 1938 'Active'
1/23/12 2949 2343 'Cancelled'
1/23/12 2949 4323 'Expired'
How do I filter the results so that if there are multiple Insurance Policies with different Status' for the same unit and same date, then we choose the Insurance Policy with the 'Active' Status first, if one doesn't exist, choose 'Cancelled', and if that doesn't exist, choose 'Expired'.
This seems to be a matter of proper ranking of InsurancePolicy's rows and then joining Unit to the set of the former's top-ranked rows:
;
WITH ranked AS (
SELECT
*,
rnk = ROW_NUMBER() OVER (
PARTITION BY hUnit
ORDER BY dtEffective DESC, sStatus, hmy DESC
)
FROM InsurancePolicy
)
SELECT
i2.dtEffective AS maxdate,
u.hMy,
i2.hmy AS InsuranceId,
i2.sStatus
FROM Unit u
LEFT JOIN ranked i2 ON i2.hUnit = u.hMy AND i2.rnk = 1
You could make this work with one SQL statement but it will be nearly unreadable to your everyday t-sql developer. I would suggest breaking this query up into a few steps.
First, I would declare a table variable and place all the records that require no manipulation into this table (ie - Units that do not have multiple statuses for the same date = good records).
Then, get a list of your records that need work done on them (multiple statuses on the same date for the same UnitID) and place them in a table variable. I would create a "rank" column within this table variable using a case statement as illustrated here:
Pseudocode: WHEN Active THEN 1 ELSE WHEN Cancelled THEN 2 ELSE WHEN Expired THEN 3 END
Then delete records where 2 and 3 exist with a 1
Then delete records where 2 exists and 3
Finally, merge this updated table variable with your table variable containing your "good" records.
It is easy to get sucked into trying to do too much within one SQL statement. Break up the tasks to make it easier for you to develop and more manageable in the future. If you have to edit this SQL in a few years time you will be thanking yourself, not to mention any other developers that may have to take over your code.