Subtraction of time stamps

Question

declare
a timestamp;
b timestamp;
c timestamp;
begin
select localtimestamp into a from dual;
select localtimestamp into b from dual;
c:=b-a;
dbms_output.put_line(c);
end;
it gives error.how to subtract two time stamps

Answer 1

Hi,
user10447332 wrote:
declare
a timestamp;
b timestamp;
c timestamp;
begin
select localtimestamp into a from dual;
select localtimestamp into b from dual;
c:=b-a;
dbms_output.put_line(c);
end;
it gives error.how to subtract two time stampsA TIMESTAMP represents a point in time.
The difference between two points in time is not another point; it is an interval. Make c an INTERVAL DAY TO SECOND, like this:
declare
     a timestamp;
     b timestamp;
     c INTERVAL DAY TO SECOND;
begin
     a := localtimestamp;
     b := localtimestamp;
     c := b - a;
     dbms_output.put_line (c);
end;The dual table is not needed very much in PL/SQL.