Oracle equivalent to SQL Server DATEPART

问题

We need to get the HOUR out of a DATETIME column (expecting values from 0 to 23 to be returned).

Is there an Oracle equivalent of the SQL Server DATEPART function?

回答1:

 SELECT to_number(to_char(sysdate, 'HH24')) FROM DUAL

回答2:

An alternative is the EXTRACT function which is an ANSI standard and also works on other DBMS, but it also requires the use of current_timestamp (also ANSI) instead of sysdate

SELECT extract(hour from current_timestamp) 
FROM dual

回答3:

I think this is what you are looking for

select to_char(current_timestamp,'HH24') from dual;

回答4:

for additional ways of using DATEPART kind of function in oracle

DATEPART:-Weekday

--This would give the day for the week for a reference start day

DECLARE
Start_day date:=to_date('30-03-2012','DD-MM-YYYY');
check_date DATE:=SYSDATE;
Day_of_week NUMBER;
i NUMBER;
BEGIN
i:=to_char(Start_day,'D');
day_of_week:=mod((to_char(check_date,'D') -(i-1)+7),7);
if day_of_week=0
THEN
day_of_week:=7;
end if;
dbms_output.put_line(day_of_week);
END;