Oracle DENSE_RANK（）

Question

I'm trying to use the DENSE_RANK() function in Oracle as a way of attaching an arbitrary "primary key" onto unique groupings of data. My dataset is a list of transactions, performed against different "ASSETS", at different "LOCATIONS" over the past several days. The dataset is pre-ordered by ASSET ASC, DATE ASC as seen below.

ASSET       LOCATION        DATE
A           LOC_A       9/1/2017
A          LOC_A        9/1/2017
A          LOC_B        9/5/2017
A          LOC_B        9/7/2017
A          LOC_A        9/11/2017
B          LOC_A        8/22/2017
B          LOC_C        8/25/2017
B          LOC_C        8/26/2017
B          LOC_A        9/2/2017
B          LOC_A        9/3/2017

When I use DENSE_RANK() OVER (ORDER BY ASSET, LOCATION), I get the following output:

ASSET       LOCATION        DATE        ACTUAL
A          LOC_A        9/1/2017        1
A          LOC_A        9/1/2017        1
A          LOC_B        9/5/2017        2
A          LOC_B        9/7/2017        2
A          LOC_A        9/11/2017       1
B          LOC_A        8/22/2017       3
B          LOC_C        8/25/2017       4
B          LOC_C        8/26/2017       4
B          LOC_A        9/2/2017        3
B          LOC_A        9/3/2017        3

However, I'm trying to figure out a way to get the value in the "EXPECTED" value shown here:

ASSET       LOCATION        DATE        ACTUAL      EXPECTED
A          LOC_A        9/1/2017        1          1
A          LOC_A        9/1/2017        1          1
A          LOC_B        9/5/2017        2          2
A          LOC_B        9/7/2017        2          2
A          LOC_A        9/11/2017       1          3
B          LOC_A        8/22/2017       3          4
B          LOC_C        8/25/2017       4          5
B          LOC_C        8/26/2017       4          5
B          LOC_A        9/2/2017        3          6
B          LOC_A        9/3/2017        3          6

Any help in working towards this would be greatly appreciated.

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My SQL is

SELECT ASSET, LOCATION, TXNDATE, 
       DENSE_RANK() OVER (ORDER BY ASSET, LOCATION) AS DENSERANK 
FROM TEMPTABLE 
ORDER BY ASSET, TXNDATE 

and yes, I am getting the "ACTUAL" result shown above.

Answer 1

You are looking for changes in asset and location . One method uses lag() and a cumulative sum:

SELECT ASSET, LOCATION, TXNDATE, 
       SUM(CASE WHEN Asset = prev_asset AND location = prev_location THEN 0
                ELSE 1
           END) OVER (ORDER BY TXNDATE) AS DENSERANK 
FROM (SELECT tt.*,
             LAG(ASSET) OVER (ORDER BY TXNDATE) as prev_asset,
             LAG(LOCATION) OVER (ORDER BY TXNDATE ) as prev_location
      FROM TEMPTABLE 
     ) tt
ORDER BY ASSET, TXNDATE;

Oracle defaults to RANGE BETWEEN rather than ROWS BETWEEN . This is the behavior you want because you have rows with the same date and they should all be treated the same.