I'm trying to implement this askTom solution to count the business days between two date fields in a table.
select count(*)
from ( select rownum rnum
from all_objects
where rownum <= to_date('&1') - to_date('&2')+1 )
where to_char( to_date('&2')+rnum-1, 'DY' ) not in ( 'SAT', 'SUN' )
I don't know how I can pass values to toms code or how to do a work around so that each time the select executes with a different set of dates and that way obtaining a similar output :
rowid | bussiness_days
I guess this could be implemented with a PL/SQL block but I'd prefer to keep it down to a query if possible. Could it be possible to pass values using &1 parameters from a select above toms one?
This is not like the original askTom, but if you're using 11gR2 you can use a Recursive CTE:
with rcte(a,b, i, is_wd) as (
select from_dt , to_dt , id, case when (to_char(from_dt, 'DY') in ('SAT','SUN')) then 0 else 1 end from t
union all
select decode(a, null, a,a+1), b, i, case when (to_char(a, 'DY') in ('SAT','SUN')) then 0 else 1 end
from rcte
where a+1 <= b
)
select i id, sum(is_wd)
from rcte
group by i
where t is a table containing "from_dates" and "to_dates"
Here is a sqlfiddle demo
Try this one:
SELECT COUNT(*)
FROM ( SELECT ROWNUM rnum
FROM all_objects
WHERE ROWNUM <= TO_DATE('2014-02-07','yyyy-mm-dd') - TO_DATE('2014-02-01','yyyy-mm-dd')+1 )
WHERE TO_CHAR( TO_DATE('2014-02-01','yyyy-mm-dd')+rnum-1, 'DY' ) NOT IN ( 'SAT', 'SUN' )
However, it has at least two issues:
It presumes the session NLS_DATE_LANGUAGE is set to English
The query gives wrong result if number of rows in ALL_OBJECTS is smaller than the amount of days between your ranges.
The version is less error-prone and faster:
WITH t AS
(SELECT TO_DATE('2014-02-01','yyyy-mm-dd')+LEVEL-1 the_date
FROM dual
CONNECT BY TO_DATE('2014-02-01','yyyy-mm-dd')+LEVEL-1 <= TO_DATE('2014-02-07','yyyy-mm-dd'))
SELECT COUNT(*)
FROM t
WHERE TO_CHAR(the_date, 'DY', 'NLS_DATE_LANGUAGE = AMERICAN') NOT IN ( 'SAT', 'SUN' )
This is another situation where a calendar table comes in handy. A calendar table has a row for every date.
If Saturday and Sunday are not business days, it's quite likely that holidays are not either. A field in the calendar table to indicate holidays makes it a lot easier to exclude them from your business days calculation.
Related
I'm surprised this question hasn't been asked. I must be missing something very obvious here, and I'm prepared for all the down votes and the 3 second answer.
In MSSQL you're able to call GETDATE() without having to depend on a database table but in Oracle SYSDATE has to come from DUAL. Is there no way to get the current date in Oracle without having to go through DUAL?
EDIT
Clearly, this doesn't have much to do with SYSDATE but more with my incorrect usage of it. See the following WHERE clause:
WHERE (extract(YEAR from ORDER_DATE) = (case when extract(month from SYSDATE()) < 11 then extract(year from SYSDATE()) else extract(year from SYSDATE())+1 end)
The above will not work, and from the answers here it seems that adding dual in there is not recommended. What's the most optimal solution here?
Avoid writing () after sysdate.
Example - using your CASE in the WHERE clause (without using DUAL):
create table T ( dt date ) ;
insert into T ( dt ) values ( sysdate ) ;
-- just write SYSDATE, not SYSDATE()
select *
from T
where ( extract ( year from dt ) ) = (
case
when extract( month from sysdate ) < 11 then
extract( year from sysdate )
else
extract( year from sysdate ) + 1
end
) ;
-- output
DT
---------
23-MAY-19
DBfiddle
Your question is about sysdate, but it really has nothing to do with sysdate.
In Oracle, all select queries require a from clause. The from clause has to contain something. So, once upon a time, someone at Oracle invented dual, along with its very awkward name, as a built-in table with exactly one row. Wikipedia even has an entry on this subject.
Not all databases require a from clause for the select -- SQL Server, MySQL, and Postgres, for instance, all allow select without one.
You can use a scalar expression, such as sysdate anywhere in a query where a scalar expression is allowed. You can repeat it as many times as you like, quite independent of what is in the from clause.
You can embed a scalar expression in a subquery in any database. For instance,
select (select sysdate from dual)
from dual
and:
select (select getdate())
Are both valid expressions. However, this is almost always bad practice and should almost always be avoided. (The one exception that I can think of is using a constant in a window functions ordering clause in SQL Server to prevent the overhead of sorting, such as row_number() over (order by (select null))).
You can just use SYSDATEwithout any explicit reference to the DUAL table.
Something along the lines of this:
INSERT INTO SOME_TABLE(some_date) VALUES (SYSDATE)
Welcome to Oracle, where everything is baffling and contrary to common sense.
Is there no way to get the current date in Oracle without having to go through DUAL?
Sysdate is a pseudo-column, which we can think of as a a function which returns the current date time. So it can used like any other function. Yes, in a query projection like ...
select sysdate from dual;
...or ...
insert into sometable (id, date_created)
values (id_seq.nextval, sysdate);
But also in a where clause. Employees hired in the last thirty days:
select * from emp
where hire_date > sysdate - 30
To find employees who were hired this year we could do this:
select * from emp
where extract(year from hire_date) = extract(year from sysdate)
...but this might perform better
select * from emp
where hire_date >= trunc(sysdate, 'YYYY') -- resolves to 2019-01-01
/
And in PL/SQL:
declare
ld date;
begin
ld := trunc(sysdate);
end;
I'm trying to find the snowflake equivalent of generate_series() (the PostgreSQL syntax).
SELECT generate_series(timestamp '2017-11-01', CURRENT_DATE, '1 day')
Just wanted to expand on Marcin Zukowski's comment to say that these gaps started to show up almost immediately after using a date range generated this way in a JOIN.
We ultimately ended up doing this instead!
select
dateadd(
day,
'-' || row_number() over (order by null),
dateadd(day, '+1', current_date())
) as date
from table (generator(rowcount => 90))
I had a similar problem and found an approach, which avoids the issue of a generator requiring a constant value by using a session variable in addition to the already great answers here. This is closest to the requirement of the OP to my mind.
-- set parameter to be used as generator "constant" including the start day
set num_days = (Select datediff(day, TO_DATE('2017-11-01','YYYY-MM-DD'), current_date()+1));
-- use parameter in bcrowell's answer now
select
dateadd(
day,
'-' || row_number() over (order by null),
dateadd(day, '+1', current_date())
) as date
from table (generator(rowcount => ($num_days)));
-- clean up previously set variable
unset num_days;
WITH RECURSIVE rec_cte AS (
-- start date
SELECT '2017-11-01'::DATE as dt
UNION ALL
SELECT DATEADD('day',1,dt) as dt
FROM rec_cte
-- end date (inclusive)
WHERE dt < current_date()
)
SELECT * FROM rec_cte
Adding this answer for completitude, in case you have an initial and last date:
select -1 + row_number() over(order by 0) i, start_date + i generated_date
from (select '2020-01-01'::date start_date, '2020-01-15'::date end_date)
join table(generator(rowcount => 10000 )) x
qualify i < 1 + end_date - start_date
I found the generator function in Snowflake quite limiting for all but the simplest use cases. For example, it was not clear how to take a single row specification, explode it into a table of dates and join it back to the original spec table.
Here is an alternative that uses recursive CTEs.
-- A 2 row table that contains "specs" for a date range
create local temp table date_spec as
select 1 as id, '2022-04-01'::date as start_date, current_date() as end_date
union all
select 2, '2022-03-01', '2032-03-30'
;
with explode_date(id, date, next_date, end_date) as (
select
id
, start_date as date -- start_date is the first date
, date + 1 as next_date -- next_date is the date of for the subsequent row in the recursive cte
, end_date
from date_spec
union all
select
ds.id
, ed.next_date -- the current_date is the value of next_date from above
, ed.next_date + 1
, ds.end_date
from date_spec ds
join explode_date ed
on ed.id = ds.id
where ed.date <= ed.end_date -- keep running until you hit the end_date
)
select * from explode_date
order by id, date desc
;
This is how I was able to generate a series of dates in Snowflake. I set row count to 1095 to get 3 years worth of dates, you can of course change that to whatever suits your use case
select
dateadd(day, '-' || seq4(), current_date()) as dte
from
table
(generator(rowcount => 1095))
Originally found here
EDIT: This solution is not correct. seq4 does not guarantee a sequence without gaps. Please follow other answers, not this one. Thanks #Marcin Zukowski for pointing that out.
I have following table tbl in database and I have dynamic joining date 1-1-2012 and I want this date is between (Fall and spring) or (spring and summer) or (summer and fall).I want query in which i passed only joining date which return semestertime and joining date in Oracle.
Semestertime joiningDate
Fall 10-13-2011
Spring 2-1-2012
Summer 6-11-2012
Fall 10-1-2015
If I understand your question correctly:
SELECT *
FROM your_table
WHERE joiningDate between to_date (your_lower_limit_date_here, 'mm-dd-yyyy')
AND to_date (your_upper_limit_date_here, 'mm-dd-yyyy`);
What about something like that:
select 'BEFORE' term,
t."Semestertime", to_char(t."joiningDate", 'MM-DD-YYYY')
from (
select tbl.*, rownum rn from tbl where tbl."joiningDate" < to_date('1-1-2012','MM-DD-YYYY')
-- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-- your reference date
order by tbl."joiningDate" desc) t
where rn = 1
union all
select 'AFTER' term,
t."Semestertime", to_char(t."joiningDate", 'MM-DD-YYYY')
from (
select tbl.*, rownum rn from tbl where tbl."joiningDate" > to_date('1-1-2012','MM-DD-YYYY')
-- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-- your reference date
order by tbl."joiningDate" asc) t
where rn = 1
This will return the "term" before and after a given date. You will probably have to adapt such query to your specific needs. But that might be a good starting point.
For example, given your business rules, you might consider using <= instead of <. You you might require to have the result displayer a column instead of rows. Bu all of this shouldn't be too had to change.
As an alternate solution using CTE and sub-queries:
with testdata as (select to_date('1-1-2012','MM-DD-YYYY') refdate from dual)
select v.what, tbl.* from tbl join
(
select 'BEFORE' what, max(t1."joiningDate") d
from tbl t1
where t1."joiningDate" < to_date('1-1-2012','MM-DD-YYYY')
union all
select 'AFTER' what, min(t1."joiningDate") d
from tbl t1
where t1."joiningDate" > to_date('1-1-2012','MM-DD-YYYY')
) v
on tbl."joiningDate" = v.d
See http://sqlfiddle.com/#!4/c7fa5/15 for a live demo comparing those solutions.
i have the following table RENTAL(book_date, copy_id, member_id, title_id, act_ret_date, exp_ret_date). Where book_date shows the day the book was booked. I need to write a query that for every day of the month(so from 1-30 or from 1-29 or from 1-31 depending on month) it shows me the number of books booked.
i currently know how to show the number of books rented in the days that are in the table
select count(book_date), to_char(book_date,'DD')
from rental
group by to_char(book_date,'DD');
my questions are:
How do i show the rest of the days(if let's say for some reason in my database i have no books rented on 20th or 19th or multiple days) and put the number 0 there?
How do i show the number of days only of the current month so(28,29,30,31 all these 4 are possible depending on month or year)... i am lost . This must be done using only SQL query no pl/SQL or other stuff.
The following query would give you all days in the current month, in your case you can replace SYSDATE with your date column and join with this query to know how many for a given month
SELECT DT
FROM(
SELECT TRUNC (last_day(SYSDATE) - ROWNUM) dt
FROM DUAL CONNECT BY ROWNUM < 32
)
where DT >= trunc(sysdate,'mm')
The answer is to create a table like this:
table yearsmonthsdays (year varchar(4), month varchar(2), day varchar(2));
use any language you wish, e.g. iterate in java with Calendar.getInstance().getActualMaximum(Calendar.DAY_OF_MONTH) to get the last day of the month for as many years and months as you like, and fill that table with the year, month and days from 1 to last day of month of your result.
you'd get something like:
insert into yearsmonthsdays ('1995','02','01');
insert into yearsmonthsdays ('1995','02','02');
...
insert into yearsmonthsdays ('1995','02','28'); /* non-leap year */
...
insert into yearsmonthsdays ('1996','02','01');
insert into yearsmonthsdays ('1996','02','02');
...
insert into yearsmonthsdays ('1996','02','28');
insert into yearsmonthsdays ('1996','02','29'); /* leap year */
...
and so on.
Once you have this table done, your work is almost finished. Make an outer left join between your table and this table, joining year, month and day together, and when no lines appear, the count will be zero as you wish. Without using programming, this is your best bet.
In oracle, you can query from dual and use the conncect by level syntax to generate a series of rows - in your case, dates. From there on, it's just a matter of deciding what dates you want to display (in my example I used all the dates from 2014) and joining on your table:
SELECT all_date, COALESCE (cnt, 0)
FROM (SELECT to_date('01/01/2014', 'dd/mm/yyyy') + rownum - 1 AS all_date
FROM dual
CONNECT BY LEVEL <= 365) d
LEFT JOIN (SELECT TRUNC(book_date), COUNT(book_date) AS cnt
FROM rental
GROUP BY book_date) r ON d.all_date = TRUNC(r.book_date)
There's no need to get ROWNUM involved ... you can just use LEVEL in the CONNECT BY:
WITH d1 AS (
SELECT TRUNC(SYSDATE, 'MONTH') - 1 + LEVEL AS book_date
FROM dual
CONNECT BY TRUNC(SYSDATE, 'MONTH') - 1 + LEVEL <= LAST_DAY(SYSDATE)
)
SELECT TRUNC(d1.book_date), COUNT(r.book_date)
FROM d1 LEFT JOIN rental r
ON TRUNC(d1.book_date) = TRUNC(r.book_date)
GROUP BY TRUNC(d1.book_date);
Simply replace SYSDATE with a date in the month you're targeting for results.
All days of the month based on current date
select trunc(sysdate) - (to_number(to_char(sysdate,'DD')) - 1)+level-1 x from dual connect by level <= TO_CHAR(LAST_DAY(sysdate),'DD')
It did works to me:
SELECT DT
FROM (SELECT TRUNC(LAST_DAY(SYSDATE) - (CASE WHEN ROWNUM=1 THEN 0 ELSE ROWNUM-1 END)) DT
FROM DUAL
CONNECT BY ROWNUM <= 32)
WHERE DT >= TRUNC(SYSDATE, 'MM')
In Oracle SQL the query must look like this to not miss the last day of month:
SELECT DT
FROM(
SELECT trunc(add_months(sysdate, 1),'MM')- ROWNUM dt
FROM DUAL CONNECT BY ROWNUM < 32
)
where DT >= trunc(sysdate,'mm')
I am trying to run a report to show a list of all dates within the past 90 days and then join that back to another table that has a date in one column and supplemental data in another. Here is how I am getting all the dates within a range:
select trunc(sysdate-90) + rownum -1 from all_objects where rownum <=90
The problem is joining this to another table on date. If I run:
select trunc(sysdate-90) + rownum -1, t.col2 from all_objects
left join (select date, col2 from table) t on trunc(sysdate-90) + rownum -1 = t.date
where rownum <=90
Then it only displays the first record from t.col2 for all values within the date range. How do I properly join these two tables?
Thanks
A better way to get the previous 90 days is to use the dual / connect by trick:
select trunc(sysdate-level) as the_date from dual connect by level <= 90
Now, you should be able to do something like:
select the_date, t.col2
from (select trunc(sysdate-level) as the_date from dual connect by level <= 90) date_tbl
left join t on date_tbl.the_date = t.date
Don't use all_objects, this is a really bad idea in terms of performance and your DBA will want to string you up. I have no idea where this idea of using all_objects came from originally, but I wish it would die!
In order to get a list of dates, you can implement a much simpler and fast bit of SQL:
SELECT TRUNC( SYSDATE ) - ROWNUM a_date
FROM DUAL
CONNECT BY ROWNUM <= (the number of days you want)
If you want an offset, you can add that
SELECT TRUNC( SYSDATE ) - ROWNUM + (the offset) a_date
FROM DUAL
CONNECT BY ROWNUM <= (the number of days you want)
If you want a different order you can wrap if in another select and then order:
SELECT a_date
FROM (
SELECT TRUNC( SYSDATE ) - ROWNUM + (the offset)
FROM DUAL
CONNECT BY ROWNUM <= (the number of days you want)
)
ORDER BY a_date ASC
You can then embed this into your existing statement, bearing in mind that you need it in a sub-select. The reason for that is so that your ROWNUM values don't get mixed up:
SELECT t.date, t.col_2
FROM ( SELECT TRUNC( SYSDATE ) - ROWNUM a_date
FROM DUAL
CONNECT BY ROWNUM <= 90 ) date_list
LEFT JOIN table t ON date_list.a_date = t.date
ORDER BY a_date DESC