Oracle: Get data for only the past half year

Question

I am writing a query in which I have to get the data for only the last half year: All data from the current date and a half year ago. Found this for 1 year in SQL but it's not working in Oracle:

SELECT ... From ... WHERE date > DATEADD(year,-1,GETDATE())

Answer 1

dateadd的等效功能是add_months

SELECT ... From ... WHERE date > add_months(sysdate, -6)

Answer 2

Use ADD_MONTHS in your filter predicate.

For example,

SQL> SELECT ADD_MONTHS(SYSDATE, -6) FROM DUAL

ADD_MONTH
---------
29-OCT-14

SQL>

Modify your query as:

WHERE date > ADD_MONTHS(SYSDATE, -6)