Difference between global temporary table and with clause

Question

what is the difference between global temporary table and with claue .(with clause is used as table in select query)

Answer 1

what is the difference between global temporary table and with claue .(with clause is used as table in select query)Its big difference between the two.
Global temporary table exists for a session or a transaction while, with clause lives only for a query.
GTT is a named permanent storage table whose data flushes away on session exit or at end of a transaction while WITH clause just provides names to a reference data within a query (which is as good as having union subquery in FROM clause)
eg
SQL> with c as
  2  (
  3  select 1 id1, 2 id2 from dual union all
  4  select 2,4 from dual union all
  5  select 3,5 from dual)
  6  select * from c
  7  /
       ID1        ID2
         1          2
         2          4
         3          5
SQL> ed
Wrote file afiedt.buf
  1  select *
  2  from
  3  (
  4  select 1 id1, 2 id2 from dual union all
  5  select 2,4 from dual union all
  6* select 3,5 from dual)
  7  /
       ID1        ID2
         1          2
         2          4
         3          5But GTT serves its purpose very well in case of session specific transaction and the scnearion with multiple users working on same data.