Calculate Total in Forms Builder using only dates.

Question

I am using Oracle 10g forms builder. I need to know how the total number of hours worked by students. In the current database, only the date is saved since everyone assumes that the students work for 2 hours each day. So if a date is present in the student's record, that means the student worked for 2 hours for that date.
However,I don't know how to calculate the total number of hours. I tried using the COUNT() function from SQL and assigning it to a variable but it keeps giving me errors.
How can I calculate the total number of hours?

Answer 1

HI,
SQL> create table hours(h date);
Table created.
SQL> insert into hours values(sysdate);
1 row created.
SQL> insert into hours values(sysdate);
1 row created.
SQL> insert into hours values(sysdate);
1 row created.
SQL> commit;
Commit complete.
select to_char(h,'DD-MM-YY HH-MI-SS') from hours;
TO_CHAR(H,'DD-MM-
19-03-08 11-06-04
19-03-08 11-06-08
19-03-08 11-06-10
SQL> select to_char(h,'HH') from hours;
TO
11
11
11
SQL> select count(to_char(h,'HH')) from  hours;
COUNT(TO_CHAR(H,'HH'))
                     3
SQL> for Forms related questions
Forms
for SQL/PL/SQL related questions
PL/SQL
HTH