Question

I’m familiar with Sybase / SQL server, where I can create a temp. table like this:

SELECT *  INTO   #temp FROM   tab1 ,         tab2  WHERE  tab1.key = tab2.fkey  SELECT *  FROM   #temp  WHERE  field1 = 'value'  

#temp only exists for the duration of this session, and can only be seen by me.

I would like to do a similar thing in Oracle, but I’m reading about ‘global temporary tables’, which don’t sound like the same thing.

How can I do the same thing in Oracle as I’m doing in Sybase?

Thanks 🙂

Answer 1

Your first approach ought to be to do this as a single query:

SELECT *  FROM    ( SELECT *  FROM   tab1 ,         tab2  WHERE  tab1.key = tab2.fkey ) WHERE  field1 = 'value'; 

For very complex situations or where temp# is very large, try a subquery factoring clause, optionally with the materialize hint:

with #temp as ( SELECT /*+ materialize */         *  FROM   tab1 ,         tab2  WHERE  tab1.key = tab2.fkey ) SELECT *  FROM   temp# WHERE  field1 = 'value'; 

If that is not helpful, go to the Global Temporary Table method.