How to use BOOLEAN type in SELECT statement

Question

I have a PL/SQL function with BOOLEAN in parameter:

function get_something(name in varchar2, ignore_notfound in boolean);

This function is

Answer 1

PL/SQL is complaining that TRUE is not a valid identifier, or variable. Set up a local variable, set it to TRUE, and pass it into the get_something function.

Answer 2

The BOOLEAN data type is a PL/SQL data type. Oracle does not provide an equivalent SQL data type (...) you can create a wrapper function which maps a SQL type to the BOOLEAN type.

Check this: http://forums.datadirect.com/ddforums/thread.jspa?threadID=1771&tstart=0&messageID=5284

Answer 3

You can build a wrapper function like this:

function get_something(name in varchar2,
                   ignore_notfound in varchar2) return varchar2
is
begin
    return get_something (name, (upper(ignore_notfound) = 'TRUE') );
end;

then call:

select get_something('NAME', 'TRUE') from dual;

It's up to you what the valid values of ignore_notfound are in your version, I have assumed 'TRUE' means TRUE and anything else means FALSE.

Answer 4

You can definitely get Boolean value from a SELECT query, you just can't use a Boolean data-type.

You can represent a Boolean with 1/0.

CASE WHEN (10 > 0) THEN 1  ELSE 0 END (It can be used in SELECT QUERY)

SELECT CASE WHEN (10 > 0) THEN 1  ELSE 0 END AS MY_BOOLEAN_COLUMN
  FROM DUAL

Returns, 1 (in Hibernate/Mybatis/etc 1 is true). Otherwise, you can get printable Boolean values from a SELECT.

SELECT CASE WHEN (10 > 0) THEN 'true' ELSE 'false' END AS MY_BOOLEAN_COLUMN
 FROM DUAL

This returns the string 'true'.