Re: function returning boolean in a where clause

>>>>> "Thomas" == Thomas Gaines <Thomas.Gaines_at_noaa.gov> writes:

 Thomas> Ken - You are partially correct. But consider this:

 Thomas> create or replace function foo(c1 in varchar2) return boolean
 Thomas> is begin
 Thomas>   if c1 = '1' then return true; else return false; end if;
 Thomas> end; /

 Thomas> set verify off prompt Enter a value on which to test the  Thomas> function: accept val

 Thomas> set serverout on begin
 Thomas>   if foo('&val') = true then
 Thomas>     dbms_output.put_line('the return from the function is
 Thomas>     true');
 Thomas>   else
 Thomas>     dbms_output.put_line('the return from the function is
 Thomas>     false');
 Thomas>   end if;
 Thomas> end; /

 Thomas> Conclusion: It is possible to do it, but only when the  Thomas> function is used under certain circumstances.

But the OP was asking if a function returning a boolean can be used in a where clause - this would be one of those circumstances where it can't be wouldn't it? Its obvious you can use it with other pl/sql functions/procedures, otherwise, what would be the point of having the boolean as a type (as opposed to just 'true/false' predicates).

Tim

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