Can we use if/else in sql statement?

Question

Hi,
Is it possible to write a sql statement like the one below (not plsql)?
if (select 'True' from dual) = 'True' -- 1
then
select 'True' from dual;  -- 2
else
  select 'False' from dual; -- 3
endBasically, I want to execute either sql 2 or 3 based on the result of sql 1. I'm not sure if this is possible using only sql and not having to write a stored proc.
What are the different ways I can implement this?
Thanks for the help.

Answer 1

Billy  Verreynne  wrote:
The case syntax is a bit funny though as there's not a single condition evaluation (like a DECODE or case structs from some other languages).
This is what I would expect a typical case struct to look like - evaluating a single condition:
case <condition>
when <value-1> then return <result-1>
when <value-n> then return <result-n>
else
return <return-z>
end
?:| You mean like this...?
SQL> ed
Wrote file afiedt.buf
  1  select empno, ename, deptno
  2        ,case deptno
  3           when 10 then 'This is Department 10'
  4           when 20 then 'And department 20'
  5           when 30 then 'And of course department 30'
  6         else
  7           'Blimey it is something else!'
  8         end as dept_desc
  9* from emp
SQL> /
     EMPNO ENAME          DEPTNO DEPT_DESC
      7369 SMITH              20 And department 20
      7499 ALLEN              30 And of course department 30
      7521 WARD               30 And of course department 30
      7566 JONES              20 And department 20
      7654 MARTIN             30 And of course department 30
      7698 BLAKE              30 And of course department 30
      7782 CLARK              10 This is Department 10
      7788 SCOTT              20 And department 20
      7839 KING               10 This is Department 10
      7844 TURNER             30 And of course department 30
      7876 ADAMS              20 And department 20
      7900 JAMES              30 And of course department 30
      7902 FORD               20 And department 20
      7934 MILLER             10 This is Department 10
14 rows selected.