I want to extract data from database where field "end_ date" is less than today's date and where end_date is not equal to null; how would I do that? I figured the second part out .. I have trouble with first part
select *
from table
where to_char(end_date) IS NOT null
Try this
...
Where end_ date is not null and
And end_date < sysdate
And, actually, I think you may not even need the first part, as if end_date is null, it certainly will not be after todays date, so try this by itself:
Where end_date < sysdate
EDIT NOTEs:
This will give you every record that has an end_date prior to the current system date and time, including those with end_Date values earlier today. If you want only those with end_Dates up to and not including midnight last night, then you need to replace "sysDate" with an expression for the date time value for midnight last night..
Where end_date < trunc(sysdate)
sysdate is oracle specific syntax to return the current system date and time. (in SQL Server, for e.g., it's a function called getDate() . The ANSI-Standard Syntax for this functionality, (which works in both Oracle and SQL Server, and should work in any ANSI-standard database) is CURRENT_TIMESTAMP.
select * from table where end_date < CURRENT_DATE and end_date IS NOT null
To show you a little more on how to use the Dates in Oracle check this out:
Selects the current date and removes 30 minutes from it where check_date is declared as a timestamp.
select current_timestamp + interval '-30' minute into check_date from dual;
Selects everything from table where end_date is not null and above now - 30 minutes
select * from table
where to_char(end_date) is not null and end_date < check_date;
select * from table where to_char(end_date,'DD-MM-YYYY') is not null and end_date < sysdate;
