How to get the latest row from my Logical Table Source?

Question

Hi everyone,
I have a SALARY_HISTORY table that holds the Salary Date and the Salary Amount for an employee, as a simple example. In my Business Model, I want to have a Display Folder called "Current Salary" and use the Where Clause restriction to derive the latest salary for each of my employees.
In standard SQL Plus, I used a nested SQL statement, e.g. "where a.SalaryDate = (select max(b.SalaryDate) from SALARY_HISTORY b where b.employeeid = a.employeeid)".
Is there anyway in the "Where Clause" filter of the LTS to derive this type of a query?
I have tried things like "DB".""."SCHEMA"."AL_SALARY_HISTORY"."SalaryDate" = EVALUATE('SELECT_PHYSICAL MAX(SALARY_DATE) FROM "DB".."SCHEMA"."AL_SALARY_HISTORY" WHERE employeeid = %1)', "DB".""."SCHEMA"."AL_SALARY_HISTORY"."employeeid"). And I know I can't use any of the analytic functions in a where clause.
So how do I go about this other than creating a View in the database or creating a function in the database to give me the maximum salary date for my employee?
Thanks
Paul

Answer 1

Hi Paul,
You could achieve this requirement using a sub query. Briefly, the steps are
1. Just create one report with max(salary_date) for each employee.
2. Create another report with SALARY_DATE included.
3. Create a filter (Based on another analysis) on this report, as employee is in(Employee of report in step1) AND SALARY_DATE IS IN(SALARY_DATE of report in step1)(this is the max_salary_date for him)
You could notice that BI Server would send two queries to the backend for this info.
Hope this helps.
Thank you,
Dhar