Oracle sql how to get the date of a week - oracle

I have the following query that gets the week of a date:
SELECT pdm.serie, rta.matricula_ant, TO_CHAR (fecha, 'ww') semana,
SUM (rta.kms_acumulados) kms,
COUNT
(DISTINCT (CASE
WHEN v.secuencia BETWEEN rta.sec_origen AND rta.sec_destino
THEN v.cod_inc
ELSE '0'
END
)
)
- 1 numincidencias
FROM (SELECT ms.tren, ms.fecha_origen_tren, ms.secuencia, ri.cod_inc
FROM r_incidencias ri, mer_sitra ms
WHERE ri.cod_serv = ms.tren
AND ri.fecha_origen_tren = ms.fecha_origen_tren
AND ri.cod_tipoin IN (SELECT cod_tipo_iincidencia
FROM v_tipos_incidencias
WHERE grupo = '45')
AND ri.punto_desde = ms.cod_estacion) v,
r_trenes_asignar rta,
r_maquinas rm,
planificador.pl_dh_material pdm
WHERE rta.fecha BETWEEN TO_DATE ('21/09/2018', 'dd/mm/yyyy') AND TO_DATE ('21/09/2018',
'dd/mm/yyyy'
)
AND rta.serie >= 4000
AND rta.matricula_ant IS NOT NULL
AND rm.matricula_maq = rta.matricula_ant
AND rm.cod_serie = pdm.id_material
AND rta.grafico BETWEEN pdm.desde AND pdm.hasta
AND v.tren(+) = rta.tren
AND v.fecha_origen_tren(+) = rta.fecha
GROUP BY pdm.serie, rta.matricula_ant, TO_CHAR (fecha, 'ww')
ORDER BY pdm.serie, rta.matricula_ant, TO_CHAR (fecha, 'ww')
For example week 1
I want to display
week 1 : 1 january - 7 january
How can I get this?

Oracle offers the TRUNC(datestamp, format) function to manipulate dates this way. You may use a variety of format strings to get the first day of a quarter, year, or even the top of the hour.
Given a particular datestamp value, Oracle returns midnight on the first day of the present week with this expression:
TRUNC(datestamp,'DY')
You can add days to a datestamp. Therefore this expression gives you midnight on the last day of the week
TRUNC(datestamp,'DY') + 6
A WHERE-clause selector for all rows in the present week might be this.
WHERE datestamp >= TRUNC(SYSDATE,'DY')
AND datestamp < TRUNC(SYSDATE,'DY') + 7
Notice that the end of the range is just before (<) midnight on the first day of the next week. You need that because you may have datestamps after midnight on the last day of the week. (Beware using BETWEEN for datestamp ranges.)
And,
SELECT TO_CHAR(TRUNC(SYSDATE,'DY'),'YYYY-MM-DD'),
TO_CHAR(TRUNC(SYSDATE,'DY')+6,'YYYY-MM-DD')
FROM DUAL;
displays the first and last dates of the present week in ISO-like format.
Date arithmetic is cool. It's worth your trouble to study the date-arithmetic functions in your DBMS at least once a year.

Related

How to add a day with a specific date using add_months function

I am trying to add a day with a specific date using add_months in oracle database.
I wrote this line:
SELECT ADD_MONTHS('01-JAN-2018', MONTHS_BETWEEN('02-JAN-2018', '01-JAN-2018')) FROM DUAL;
this returns:
01-JAN-18
Why doesn't it return 02-JAN-18?? Can I add one day to the date using this function?
Why doesn't it return 02-JAN-18??
According to MONTHS_BETWEEN documentation,
The MONTHS_BETWEEN function calculates the number of months between
two dates. When the two dates have the same day component or are both
the last day of the month, then the return value is a whole number.
Otherwise, the return value includes a fraction that considers the
difference in the days based on a 31-day month
So,
select MONTHS_BETWEEN('02-JAN-2018', '01-JAN-2018') FROM DUAL ;
yields
.0322580645161290322580645161290322580645
ADD_MONTHS returns the date date plus integer months.
So, .0322.. is considered as integer 0 and your query is equivalent to
SELECT ADD_MONTHS('01-JAN-2018', 0) FROM DUAL;
In order to add 1 months, simply take the difference of two dates.
SELECT ADD_MONTHS(DATE '2018-01-01', DATE '2018-01-02' - DATE '2018-01-01') FROM DUAL;
Or better, add an INTERVAL of 1 month
SELECT DATE '2018-01-01' + INTERVAL '1' MONTH FROM DUAL;
To answer your question, add 1 day, simply use
SELECT DATE '2018-01-01' + 1 FROM DUAL;

Oracle DB to_date with year - to_date(2017,'YYYY') unexpected return

While writing few queries I needed to return only those rows that have date column set in this year (2017) , that's not my problem I know how to write this query in couple of diffrent ways, but I came across something strange and unexpected for me. Can anyone explain why Oracle db 11.2 is behaving this way?
select sysdate from dual
returns:
2017/12/05 09:22:27
select to_date(2017,'YYYY'),trunc(sysdate,'YYYY') from dual
returns :
2017/12/01 00:00:00 2017/01/01 00:00:00
select to_date(2017,'YYYY'),trunc(sysdate,'YYYY') from dual
where trunc(sysdate,'YYYY') = to_date(2017,'YYYY')
no rows returned
Why does to_date(2017,'YYYY') returns 2017/12/01, will it return 2017/01/01 next month? Why does it work that way? I would expect it to always return 2017/01/01 no matter the current month (if month part is indeed changing depending on sysdate).
In Oracle, TO_DATE will assume that:
If you do not specify the year then it is the current year;
If you do not specify the month then it is the current month;
If you do not specify the day then it is the first day of the month;
If you do not specify the hours then it is the midnight hour (0);
If you do not specify the minutes then it is 0 minutes past the hour; and
If you do not specify the seconds then it is 0 seconds into the minute.
You are specifying only the year (2017) so it will be:
Zero minutes and seconds past midnight of the first day of the current month of the year you specify (2017).
If you want the first day of the year then specify the month (and preferably the rest of the date):
select to_date( '201701','YYYYMM'),
trunc(sysdate,'YYYY')
from dual
where trunc(sysdate,'YYYY') = to_date( '201701','YYYYMM' )
Or use a date literal:
select DATE '2017-01-01',
trunc(sysdate,'YYYY')
from dual
where trunc(sysdate,'YYYY') = DATE '2017-01-01'

select unique trunc(sysdate-370 + level, 'IW') AS datetime from dual connect by level <= 360 order by datetime

Can someone explain me what does the below oracle query do and what is it's output?
select unique trunc(sysdate-370 + level, 'IW') AS datetime from dual
connect by level <= 360 order by datetime;
select sysdate-370 + level AS datetime
from dual
connect by level <= 360;
Will generate 360 rows starting with the current date/time minus 370 days plus one day per row. So rows between 369 and 10 days before the current date/time.
TRUNC( datetime, 'IW' ) will truncate the date to the start of the ISO week (midnight on Monday of that week - irrespective of the NLS settings for date language and/or territory that affect some other options for truncating dates). So you will end up with duplicate rows for each generated row that is in the same week.
The UNIQUE keyword will get rid of those duplicate rows.
The order by datetime will order the results in ascending date order - however, the rows are generated in ascending order so this clause is unnecessary.
So the output will be 52 or 53 rows (depending on what the current day of the week is) starting with Monday midnight of each week containing the date 369 days before the current day up until the week containing 10 days before the current date.
The output (when run on 13th September 2017) is 52 rows (I skipped a few):
05-SEP-2016
12-SEP-2016
19-SEP-2016
26-SEP-2016
03-OCT-2016
...
31-JUL-2017
07-AUG-2017
14-AUG-2017
21-AUG-2017
28-AUG-2017
According to documentation trunc(dateval, 'IW') truncates to:
Same day of the week as the first day of the calendar week as defined by the ISO 8601 standard, which is Monday
connect by level <= N is a trick for producing a set of N rows with level values from 1 to N.

How can I use an expression in my where clause to return a dynamic date range for my query

I am working in BIDS 2008r2 on a SSRS report that pulls data from an Oracle database.
I have a where clause that uses a hard date range, I want to change it to an expression that will dynamically change as time progresses.
This is the where clause that currently works to return the 1st day of the previous month to the last day of the previous month. ie I am looking for all data from the previous month
WHERE CHRGDTTM BETWEEN {ts '2015-12-01 00:00:00'} AND {ts '2015-12-31 23:59:00'}
I have written an expression that returns the beginning of last month:
DateAdd(DateInterval.Month, -1, DateSerial(Year(Date.Now), Month(Date.Now), 1))
and one that returns the end of last month:
DateAdd(DateInterval.Minute, -1, DateSerial(Year(Date.Now), Month(Date.Now), 1))
How do I get those into my where clause?
Thank you.
If you want to do this entirely within the Oracle where clause you can do:
WHERE CHRGDTTM >= ADD_MONTHS(TRUNC(sysdate, 'MM'), -1)
AND CHRGDTTM < TRUNC(sysdate, 'MM')
The TRUNC(date) function truncates the supplied date - the system date in this case; by default it removes the time part so gives you midnight this morning, but this modified that behaviour with the MM format model, and gives you midnight on the first of the current month. So today TRUNC(SYSDATE, 'MM') gives you 2016-01-26 00:00:00. You can use that as it is for the upper end of your date range.
The ADD_MONTHS() function, well, adds a number of months, -1 here to give you 2015-12-01 00:00:00 instead. Put together that gives you everything from 2015-12-01 00:00:00 up to, but no including, 2016-01-01 00:00:00, which is equivalent to your BETWEEN range.
You could also use an interval calculation to get the start of the previous month:
WHERE CHRGDTTM >= TRUNC(sysdate, 'MM') - INTERVAL '1' MONTH
AND CHRGDTTM < TRUNC(sysdate, 'MM')
which has the same effect, and is safe as you're always going to end up with a valid date from the calculation; dates at the ends of months can be more problematic.
You can read more about datetime/interval arithmetic in the documentation.
As an alternative, you can create two parameters of type Date/Time and set the Default Values for the parameters with the expressions you've developed. Then in the query it just becomes WHERE CHRGDTTM BETWEEN :StartDate AND :EndDate. If the user needn't worry about this, set the visibility to Hidden for both.

Oracle ORA-01839: date not valid for month specified Leap Year

Oracle 11g
here is a quick one hopefully.
Below is part of a script that gets date only from from the next month
first day of next month to last day. But today 29th feb it thrown an error of
ORA-01839: date not valid for month specified
M.MS_DATE between trunc(sysdate + interval '1' month,'MM') and last_day(sysdate + interval '1' month)
Is there a way round this. Many thanks
I have seen this as well and I consider this a bug in Oracle.
The workaround is to use add_months() instead :
between trunc(add_months(sysdate,1),'MM') and last_day(add_months(sysdate,1));
I would probably use add_months() as a_horse_with_no_name suggests, but just as an alternative if you want to use intervals, you can move the point you do the truncation in the first expression, and include the same truncation in the second expression:
select trunc(sysdate, 'MM') + interval '1' month as first_day,
last_day(trunc(sysdate, 'MM') + interval '1' month) as last_day
from dual;
FIRST_DAY LAST_DAY
---------- ----------
2015-02-01 2015-02-28
This works because all months have a first day, so you don't trip over the documented caveat.
When interval calculations return a datetime value, the result must be an actual datetime value or the database returns an error

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