Using the result of a subselect in another part of the select

Question

Does anyone know if 9i can use the results of a subselect in a select in another part of the select. For example:
select x, (select y from sometable) as ssvar, z, (select abc from someothertable where somecolumn=ssvar) from yetanothertable
Anyone? We have a bunch of Sybase queries we are porting over and they use this extensively. It looks like the 9i docs say this may not be possible, but I really wanted to be sure before I rewrite the queries.
-Lou

Answer 1

From your example, an inline view seems most appropriate to me...
select max_table.table_name, column_name
from user_tab_columns, (
select max(table_name) as table_name
from user_tables) max_table
where max_table.table_name = user_tab_columns.table_name
However, if your actual usage is more complicated, you might want to look at 'subquery factoring' (new in 9i). It doesn't really do much good for this example but here's the syntax...
with max_table as (
select max(table_name) as table_name
from user_tables)
select max_table.table_name, column_name
from max_table, user_tab_columns
where user_tab_columns.table_name = max_table.table_name
Richard