Dates of Price Changes per Article

Question

Hi,
I have a table with the following columns:
Date
ArticleID
OriginalPrice
NowPrice
PriceReduction
I'd like to create calculated columns as follows:
the date of last/first price reduction per ArticleID
the date of lowest/highest NowPrice per ArticleID
the number of price changes (i.e. different price reductions) per ArticleID
I could create calculated columns to calculate lowest/highest NowPrice per ArticleID. But I don't know how to solve the questions above.
I enclose a dropbox link to an example Excel 2013 file:
PP_PriceChange.xlsx
Thank you for any advice!
Chiemo

Answer 1

Hello Greg2178,
thank you for your advice and for providing the updated workbook. The allexcept() function is indeed very interesting and helpful.
I am still a newbie with powerpivot and learn day by day and challenge by challenge.
I checked the measures and some are unfortunately not working as expected.
In order to make it more obvious what I am looking for I repeat the core table columns of table1:
Date      ArticleID   OriginalPrice   NowPrice  PriceReduction
11/1      1001         100              
50              -50%
11/26    1001         100               50              -50%
11/27    1001         100               50              -50%
11/29    1001         100               50              -50%
11/1      1002          50                40             
-20%
11/26    1002          50                30             
-40%
11/27    1002          50                20             
-60%
11/29    1002          50                25             
-50%
11/1      1003          20               
30              +50%
11/26    1003          20                20                 
0%
11/27    1003          20                10              
-50%
11/29    1003          20                20                 
0%
Let me concentrate on the biggest challenges for me:
Number of Price Changes (compared to original or previous price) per ArticleID:
the correct answer for article 1001 would be = 1, for 1002 = 4, for 1003 = 4
formula provided in your workbook gives 4 price changes for any article
I would think to solve this by 3 different steps, i.e. calculated columns:
Step1: Calculate the previous price reduction. Unfortunately the following formula does not work (I think because of the Max() function; see column "FormerPriceReduction" in  updated model):
=CALCULATE(MAX(Table1[PriceReduction]);FILTER(Table1; EARLIER(Table1[ArticleID])=Table1[ArticleID] && EARLIER(Table1[Date])>Table1[Date]))
Step2: Check if current price reduction differs from previous price reduction; if yes = 1, if no = 0; formula:
=IF([PriceReduction]-[FormerPriceReduction]<>0;1;0)
Step3: Sum of all changes under Step2 = number of price changes. Formula:
=CALCULATE(SUM([PriceChange=1]);FILTER(Table1;Table1[ArticleID]=EARLIER(Table1[ArticleID])))
Please see updated excel workbook : https://www.dropbox.com/s/g075xhhbo7jyttw/PP_PriceChangeUpdate.xlsx?dl=0
Date of Last Price Reduction (i.e. date of last price change) per ArticleID:
The correct answer would be for article 1001 = 11/01, for 1002 = 11/29, for 1003 = 11/29
The formula provided delivers for 1001 = 11/29, for 1002 = 11/29 and for 1003 = 11/27
I would think that the use of the correct formula from Step1 above could be a starting point for getting the correct answer
(First) Date of Lowest Price:
The correct answer would be for article 1001 = 11/01, for 1002 = 11/27, for 1003 = 11/27
I think the formula provided gets the wrong results because it relates to the column „MinNowPrice“ which lists for each date the all time lowest price
Do you have any ideas to solve this problem?
Sorry that I cannot contribute much to the solution. I hope you can give me some more hints.
Thank you very much
Chiemo