santhosh kumar vk wrote: Could you please tell me is there any differenct using the (+) operator in WHERE clause and FROM clause
As far as I know, the (+) cannot be used in the FROM clause.
How it will work in DECODE Function.
As Chris has already mentioned, this probably indicates an outer join. I guess that lines from the pc table will be included, even if there isn't a record in the ml table such that the DECODE expression would match pc.catg_c.
It would be much more readable when converted to ANSI join syntax, in my opinion.