When you think you need write with clause of answers.

Question

This thread is not a question.
I will use this thread to refer to in other threads, when anyone ask me "Do I have to write with clause?"
The answer is NO you don't have to write with clause AT ALL.
with clause is create temp table on the fly.
with tempTable as(
select 1 as column1,2 as column2 from dual union all
select 1 as column1,2 as column2 from dual union all
select 1 as column1,2 as column2 from dual)
select * from tempTable;If you have created the Table,you do NOT have to write with clause like above.
therefore you can write like below.
select * from tempTable;

Answer 1

user13091888 wrote:
I dont's see reason why you created this thread but...
Global temporary table and with clause is not equivalent. If you want select from temp table you have insert here some data first and then oracle have to create temp segment for your session. If you use with clause there is not neccessary to create temp segment for you unless you run out of your available memory e.g. making sorts, big hash joins etc.?:|
He never mentioned Global Temporary Tables.
He was saying that the subquery factoring clause is used in answers on the forum where people are temporarily creating the data for the purposes of the answer, rather than create a real table. I would guess English isn't his first language, so the way he worded it could be misconstrued, but it's fairly obviousl what he was saying, even though I agree the thread is pointless.