Is there a way to give a subquery an alias in Oracle 11g SQL?

Question

Is there a way to give a subquery in Oracle 11g an alias like:

select * 
from
    (select client_ref_id, request from some_table where message_type = 1) abc,
            


        

Answer 1

You can give a query a name or alias with CTE’s (Common Table Expressions) aka WITH clause aka by Oracle as Subquery Factoring:

WITH abc as (select client_ref_id, request from some_table where message_type = 1)
select * 
from abc
    inner join 
    (select client_ref_id, response  from some_table where message_type = 2) defg
       on abc.client_ref_id = def.client_ref_id;