question

The 'old' syntax in Oracle uses the + sign to the right of the table being joined to, while in T-SQL the \* was on the "correct side" of the equal sign. It is actually great news that they finally discontinued support for the old syntax because it would occasionally cause issues since all conditions (join conditions and the after join predicates) were bunched together in the where clause so there was no guarantee that they would be executed in the correct order. For example, suppose you have a table named Employee and another table named Dependent which has 0-to-many relationship to Employee. Now, try to write a query using the old syntax to return records for those employees which don't have dependents. It would seem that this should work:

select
    e.*
    from dbo.Employee e, dbo.Dependent d
    where e.ID *= d.ID and d.ID and d.ID is null

Unfortunately, the above fails returning all employee records. This is because d.ID is null is evaluated first, before the join condition, and since none of the Dependent records has ID is null, all records are eliminated and therefore, all employee records are returned. Restating it properly with left join works as expected of course.