Data Conversion issue

Question

Hello I'm new to Oracle DB and still learn SQL.
I have a problem with data conversion in a CASE expression.
Example:
select ... ,     
CASE column WHEN 1 THEN
select max(column)
from table
where ...
ELSE 0 END AS value,
from     ...
where ...
order by ...
What I'm basically intend to do is to select a value from another table depending on the value of
a special column.
The problem now is that the
select max(column)
from table
where ...
statement in its original form selects the right value as float (e.g. 0.24)which I need.
But the same statement embedded in the CASE expression returns (e.g. 0 ) which seems to be the same result converted to an integer or something.
I tried to convert the result in the CASE expression but without success.
Does anybody know what could cause this behavior and how to fix it ?
Thanks for any help with this.

Answer 1

Welcome to the forum!
Whenever you have a problem, post a complete script that people can run to re-create the problem. Include CREATE TABLE and INSERT statements for a little sample data if necessary. (A lot of folks show the problem using commonly available tables, such as those in the scott or hr schemas, so they don't have to post any sample data.)
if your problem involves an error message, post the complete error message you're getting, including line numbers.
Always say which version of Oracle you're using, e.g. 10.2.0.1.0.
Sorry, I can't re-create the problem.
I did something as similar as I could to what you posted:
SELECT       deptno
,       CASE deptno
          WHEN  10
          THEN  (
               SELECT  MAX (sal)
               FROM     scott.emp
               WHERE     deptno     = d.deptno
          ELSE  0
       END          AS value
,       dname
FROM       scott.dept     d
WHERE       deptno     <= 30
ORDER BY  deptno
;And it ran, producing this output:
`   DEPTNO      VALUE DNAME
        10       5000 ACCOUNTING
        20          0 RESEARCH
        30          0 SALES
886562 wrote:Hello I'm new to Oracle DB and still learn SQL.I've been using Oracle for 20 years, and still learn SQL.
select ... ,     
CASE column WHEN 1 THEN
select max(column)
from table
where ...
ELSE 0 END AS value,
The problem now is that the
select max(column)
from table
where ...
statement in its original form selects the right value as float (e.g. 0.24)which I need.
But the same statement embedded in the CASE expression returns (e.g. 0 ) which seems to be the same result converted to an integer or something.Are you sure that 0 is being returned by the sub-query in the THEN clause, and not by the ELSE clause?
I tried to convert the result in the CASE expression but without success.What did you try? Post your code.
What problem did you have? Post the error message.
Edited by: Frank Kulash on Sep 21, 2011 6:15 AM