Verify column format - HH:MM, HH between 00 & 12 and MM between 00 & 59

Question

CREATE TABLE test
(t_TIME AS VARCHAR2(5));
INSERT INTO test VALUES('18:30');
INSERT INTO test VALUES('  : ');
INSERT INTO test VALUES('15:00');
INSERT INTO test VALUES(09:00');This represent a table of data that have from source, so while time data is varchar2 is irrelevant at this stage. The first phase/rule to apply is:
If t_time isnt in format of HH:MM, HH between 00 and 12 and MM between 00 and 59, then it has be set to 00:00.
Any ideas how this can be done.

Answer 1

You are really very boring.
Do you plan to outsource the complete application development to this forum?
create or replace verify_time(p_tme in varchar2) return varchar2 is
dummy date;
begin
select to_date('11-09-2001 '||p_time,'dd-mm-yyyy hh24:mi')
into dummy
from dual;
return 'T';
exception
when others then return 'F';
end;
It is as simple as that. And you couldn't do that yourself?
Sybrand Bakker
Senior Oracle DBA