Decode help in sql

Question

i m writing an sql query to print records
select role_name,date_created,date_modified,createdbyuser_id,modifiedbyuser_id from t_role;
This returns me the the rows in table t_role.
But what i want is instead of the id of the person being printed in createdbyuser_id and modifiedbyuser_id, it shud provide me the username from another table user by checking the user_id field of table user.For this i used the fuction decode .But it oesnt work
select role_name,date_created,date_modified,(select user_name from user where user_id=createdbyuser_id),(select user_name from user where user_id=modifiededbyuser_id) from role;
kindly point out the mistake.
Shefali

Answer 1

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i m writing an sql query to print records
>>
and
<<
1) tried this
select a.role_name,a.date_created, a.date_modified, b.user_name, c.user_name from role a, user b, user c where b.user_Id = a.createdbyuser_Id and c.user_Id = a.modifiedbyuser_Id;
But getting this error::
ORA-20001: Your query contains duplicate alias names, queries used for reports require unique alias names.
Error saving column settings
>>
so you are working with report writer ?
the error message is telling you all you need.
just change :
select  a.role_name ,a.date_created, a.date_modified
      , b.user_name, c.user_name
  from  role a, user b, user c
where b.user_Id = a.createdbyuser_Id
   and c.user_Id = a.modifiedbyuser_Id
;to
select  a.role_name ,a.date_created, a.date_modified
      , b.user_name_creator, c.user_name_modifier
  from  role a, user b, user c
where b.user_Id = a.createdbyuser_Id
   and c.user_Id = a.modifiedbyuser_Id
;