问题
SELECT ORDER_NUM, CUSTOMER_NUM, CUSTOMER_NAME, ADD_DAYS (ORDER_DATE, 20)
FROM CUSTOMER, ORDERS;
Oracle Express says ADD_DAYS invalid? Any ideas what Am I doing wrong?
回答1:
If you want to add N days to your days. You can use the plus operator as follows -
SELECT ( SYSDATE + N ) FROM DUAL;
回答2:
You can use the plus operator to add days to a date.
order_date + 20
回答3:
In a more general way you can use "INTERVAL". Here some examples:
1) add a day
select sysdate + INTERVAL '1' DAY from dual;
2) add 20 days
select sysdate + INTERVAL '20' DAY from dual;
2) add some minutes
select sysdate + INTERVAL '15' MINUTE from dual;
回答4:
It's Simple.You can use
select (sysdate+2) as new_date from dual;
This will add two days from current date.
回答5:
Some disadvantage of "INTERVAL '1' DAY" is that bind variables cannot be used for the number of days added. Instead, numtodsinterval can be used, like in this small example:
select trunc(sysdate) + numtodsinterval(:x, 'day') tag
from dual
See also: NUMTODSINTERVAL in Oracle Database Online Documentation
来源：https://stackoverflow.com/questions/27451226/add-days-oracle-sql