CODEWITHSUNDEEP
sql
Saim
Saim

Reputation: 15

How to Identify Increasing or Decreasing Trend Using SQL Query

I have data like 

EmpID   Salary Paid Date Salary Paid
100 628           1/11/2019
100 1086              1/25/2019
100 1055              2/8/2019
100 981           2/22/2019
100 653           3/8/2019
100 871           3/22/2019
100 385           4/18/2019
101 2032              1/4/2019
101 3466              1/18/2019
101 2652              2/1/2019
101 2013              4/26/2019

Is there any way identify a "Trend Decreasing" flag (Yes/ No). only one record or preferably decision on "Decreasing" can be repeat for all the rows. something like 

EmpID   Salary Paid Date Salary Paid    Decreasing Flag
100 628                1/11/2019    Y
100 1086                   1/25/2019    Y
100 1055                   2/8/2019 Y
100 981                2/22/2019    Y
100 653                3/8/2019 Y
100 871                3/22/2019    Y
100 385                4/18/2019    Y
101 2032                   1/4/2019 N
101 3466                   1/18/2019    N
101 2652                   2/1/2019 N
101 2013                   4/26/2019    N

Y/N is the valued for each empid (not for each row)

Thanks

I have tired but couldn't find a proper way

Upvotes: 0

Views: 1822

Answers (1)

Gordon Linoff
Gordon Linoff

Reputation: 1269493

If you want to compare the first and last salaries for the trend, you can use first_value():

select t.*,
       (case when first_value(salary) over (partition by empid order by paid_date) <
                  first_value(salary) over (partition by empid order by paid_date desc)
             then 'N' else 'Y'
        end) as decreasing_flag
from t;

Note that the syntax for first_value() may vary slightly among databases.

Upvotes: 3

Related Questions