Walentyna Juszkiewicz:

Need to emulate Oracle Ignore Nulls in aggregate functions (LEAD and LAG) in PostgreSQL.

SELECT empno,
   ename,
   orig_salary,
   LAG(orig_salary, 1, 0) IGNORE NULLS OVER (ORDER BY orig_salary) AS sal_prev
FROM   tbl_lead;

If there are NULL, it should return the latest not null value.

I've tried it via PostgreSQL user defined aggregate functions, but it's rather hard to understand methodology of it http://ift.tt/29ms7Ew

The solution can't be realized via WITH clause or sub-query since it it used in complex query.

On the left panel data without Ignore NULLS. On the right panel data with IGNORE NULLS. So I need to get right variant in PostgreSQL