Oracle SQL : Value will be true every after 30 days - sql

I'm not really good in Oracle SQL but i'm trying to check a date something like this
For example: 01-Jan-2000
How can I check if 30 days passed already, and also for 60 months and so on.
Basically i need to make a condition that will return true after a month and so on. i can check it 1 by 1 but it's obviously not good.
DECLARE
appn_date DATE;
BEGIN
appn_date := Trunc(TO_DATE ('10-AUG-2016'));
IF (appn_date = trunc(sysdate) - interval '30' day) THEN
DBMS_OUTPUT.PUT_LINE('Yes');
ELSE
DBMS_OUTPUT.PUT_LINE('No');
END IF;
END;
It should output Yes because 30 days passed already, but it will also output Yes after 60 days, 90 days and so on. I think modulo will work on this. any idea?

To check if that column's value is older then 30 days, use:
where the_date_column <= sysdate - interval '30' day
or a bit shorter but identical
where the_date_column <= sysdate - 30
For months you need to use add_months()
where the_date_column <= add_months(sysdate, -60);
As Oracle's DATE isn't really a "date" but a "datetime" you might need trunc() (for both: the date column and sysdate) if you don't want to consider the time part.
See the manual for details on how to specify intervals and the available date functions

Related

count the number of days of current month from day 1 until yesterday

I am trying to calculate the number of days of the current of month from day 1 until yesterday without the need of changing the count manually. The original SQL as below:
select order_id
from orders
where date > dateadd(-23 to current_date) and date < 'today'
the desired code is something like
select order_id
from orders
where date > dateadd(datediff(day,firstdayofthemonth,current_date) to current_date) and date < 'today'
Appreciate any help
In firebird you could do:
WHERE
date >= DATEADD(1 - EXTRACT(DAY FROM CURRENT_DATE) DAY TO CURRENT_DATE)
AND date < CURRENT_DATE
In addition to the answer provided by Mark, you can also use BETWEEN (starting with Firebird 2.0.4)
WHERE
date BETWEEN current_date - extract(day from current_date) + 1
AND current_date - 1
P.S. all those answers rely upon DATE data type (thus, date column and CURRENT_DATE variable) having no time part. Which is given for modern SQL dialect 3. But if Dialect 1 would get used it is not given.
https://firebirdsql.org/file/documentation/reference_manuals/fblangref25-en/html/fblangref25-commons-predicates.html
https://firebirdsql.org/file/documentation/reference_manuals/fblangref25-en/html/fblangref25-background.html#fblangref25-structure-dialects
In addition to the answer provided by GMB, you can also use fact that Firebird allows addition of days to a date without needing to use dateadd:
date > current_date - extract(day from current_date)
and date < current_date

How to convert a single Oracle datetime into minutes?

I wish to convert a single Oracle datetime value to minutes.
As an example, I need to convert the current date/time alone into minutes, i.e.:
select (sysdate)*24*60 from dual
but this is giving me an error.
I basically need to perform a check to see that a certain operation cannot be performed until 30 minutes before a particular date/start time, that exists in the database.
So if the Start Time in the DB is:
24/04/2014 22:00:00 and the current date/time (SYSDATE) is 24/04/2014 21:29:59,
then operation CANNOT be performed but if the current date/time (SYSDATE) is:
24/04/2014 21:30:00,
then operation CAN be performed.
You probably want something like
startTime - interval '30' minute >= sysdate
or
startTime >= sysdate + interval '30' minute
You could also subtract the two date values which gives you the number of days between them and multiply
(startTime - sysdate)*24*60 >= 30
but I generally find the interval notation clearer and easier to read. It's also easier to structure in a way that allows you to use indexes on columns like startTime.
select (sysdate - trunc(sysdate)) *24 *60 from dual
You seem to want to know if the seconds component of sysdate is 0. So, test for that:
where extract(second from sysdate) = 0
Oops, I misread the question. You just need a difference of 30 minutes. That is also easy:
where starttime <= sysdate + 30/(24*60)
When you add an integer to a datetime, it is interpreted as a number of days. The expression 30/(24*60) is an expression for half an hour measured in days.

How to retrieve the records based on a date from oracle database

I have a table with date column in it. I need to fetch the records from it based on
the given date.
Currently when i used the query:
select * from workingemployee_data where created_date like '20-Jan-2012'
I am getting those records which have created_date on 20-Jan-2012
But i want to get the records those were created 10 days earlier to a given
date (i.e) 20-Jan-2012.
Please suggest me on this.
This gives all records between today and 10 days ago:
SELECT *
FROM workingemployee
WHERE created_date BETWEEN sysdate - INTERVAL '10' DAY
AND sysdate
This gives all records entered exactly 10 days ago:
SELECT *
FROM workingemployee
WHERE created_date = sysdate - INTERVAL '10' DAY
Replace sysdate with exact date if you want.
Why do you use like and not = ?
Assuming that created_date is of type DATE, it's bad practice to rely on implicit conversion according to NLS_DATE_FORMAT (this is what happens when you compare a date and a string)
dd-mon-yyyy isn't a good format for querying since it deffers according to NLS_LANGUAGE better use mm for months numbers
So, either use #mvp's answer or do something like this:
SELECT *
FROM workingemployee
WHERE trunc(created_date) = to_date('20-01-2013', 'dd-mm-yyyy') - 10
SELECT *
FROM workingemployee
WHERE created_date > sysdate - INTERVAL '10' DAY;

How do you find results that occurred in the past week?

I have a books table with a returned_date column. I'd like to see the results for all of the books with a returned date that occurred in the past week.
Any thoughts? I tried doing some date math, but Postgres wasn't happy with my attempt.
You want to use interval and current_date:
select * from books where returned_date > current_date - interval '7 days'
This would return data from the past week including today.
Here's more on working with dates in Postgres.
Assuming returned_date is data type date, this is simplest and fastest:
SELECT * FROM books WHERE returned_date > CURRENT_DATE - 7;
now()::date is the Postgres implementation of standard SQL CURRENT_DATE. Both do exactly the same in PostgreSQL.
CURRENT_DATE - 7 works because one can subtract / add integer values (= days) from / to a date. An unquoted number like 7 is treated as numeric constant and initially cast to integer by default (only digits, plus optional leading sign). No explicit cast needed.
With data type timestamp or timestamptz you have to add / subtract an interval, like #Eric demonstrates. You can do the same with date, but the result is timestamp and you have to cast back to date or keep working with timestamp. Sticking to date is simplest and fastest for your purpose. Performance difference is tiny, but there is no reason not to take it. Less error prone, too.
The computation is independent from the actual data type of returned_date, the resulting type to the right of the operator will be coerced to match either way (or raise an error if no cast is registered).
For the "past week" ...
To include today make it > current_date - 7 or >= current_date - 6. But that's typically a bad idea, as "today" is only a fraction of a day and can produce odd results.
>= current_date - 7 returns rows for the last 8 days (incl. today) instead of 7 and is wrong, strictly speaking.
To exclude today make it:
WHERE returned_date >= current_date - 7
AND returned_date < current_date
Or:
WHERE returned_date BETWEEN current_date - 7
AND current_date - 1
To get the last full calendar week ending with Sunday, excluding today:
WHERE returned_date BETWEEN date_trunc('week', now())::date - 7
AND date_trunc('week', now())::date - 1
BETWEEN ... AND ... is ok for data type date (being a discrete type), but typically the wrong tool for timestamp / timestamptz. See:
How to add a day/night indicator to a timestamp column?
The exact definition of "day" and "week" always depends on your current timezone setting.
What math did you try?
This should work
select * from books where current_date - integer '7'
Taken from PostgreSQL Date/Time Functions and Operators

Checking timestamps in PL/pgSQL

If I have a function in PL/pgSQL that takes in a timestamp, what is the best way to identify whether that date is less than 12 months in the past?
e.g.
CREATE FUNCTION do_something(foo timestamp) ....
-- IF foo is less than 12 months in the past THEN
-- do something
-- END IF;
END;
Read about intervals on PostgreSQL doc: Date Types. Use something like:
where foo < CURRENT_TIMESTAMP - interval '12 months'
Or, equivalently: age(foo) < interval '12 months'