Starting with Oracle9i, the confusing outer join syntax using the ‘(+)’ notation has been superseded by ISO 99 outer join syntax. As we know, there are three types of outer joins, left, right, and full outer join. The purpose of an outer join is to include non-matching rows, and the outer join returns these missing columns as NULL values.
Let’s review the syntax differences between these variations in join syntax:
Left outer join: Oracle8i
select
last_name,
department_name
from
employees e,
departments d
where
e.department_id = d.department_id(+);
Left outer join: Oracle9i
select
last_name,
department_name
from
employees e
left outer join
departments d
on
e.department_id = d.department_id;
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source: http://www.algolist.net/Algorithms/Sorting/Quicksort. The divide-and-conquer strategy is used in quicksort. Below the recursion step is described: 1st: Choose a pivot value. We take the value of the middle element as pivot value, but it can be any value(e.g. some people would like to pick the first element and do the exchange in the end) 2nd: Partition. Rearrange elements in such a way, that all elements which are lesser than the pivot go to the left part of the array and all elements greater than the pivot, go to the right part of the array. Values equal to the pivot can stay in any part of the array. Apply quicksort algorithm recursively to the left and the right parts - the previous pivot element excluded! Partition algorithm in detail: There are two indices i and j and at the very beginning of the partition algorithm i points to the first element in the array and j points to the last one. Then algorithm moves i forward, until an element with value greater or equal
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