Decode with IN

Question

Hi,
Is it possible to do a decode when using an 'IN' in the where clause e.g.
select
     count(*)
from
     hr.employees e
where
     e.JOB_ID in (select decode('B','A','SH_CLERK','(''IT_PROG'',''MK_MAN'')') from dual)
The above returns 0 where as the following code returns 6
select
     count(*)
from
     hr.employees e
where
     e.JOB_ID in ('IT_PROG','MK_MAN')
Thanks in advance
Adam

Answer 1

Hallo adennis,
no, you cannot use in directly with decode:
select * from emp where ename in (decode(1,1,'KING,BLAKE'))
no rows selectedthe problem is that you get here
select * from emp where ename in ('KING,BLAKE')
Correct is
select * from emp where ename in ('KING','BLAKE')
You compare ename with string 'KING,BLAKE' and doesn't find any occurences.
You can do it with dynamic SQL with IN as literal string, but it leads to hard parse
and poor performance.
You can do it indirect
select * from emp where ename = (decode(1,1,'KING'))
UNION ALL
select * from emp where ename = (decode(1,1,'BLAKE'))or
select * from emp where ename = (decode(1,1,'KING'))
                     or ename = (decode(1,1,'BLAKE'))
[pre]
HTH
Regards
Dmytro