This query:
select count(*), trim(data_date)
from man
where data_status = 'received' and data_date > sysdate-7
group by trim(data_date);
gives result like:
199 05-APR-16
But this query:
select count(*), trim(data_date)
from man
where data_status = 'received' and trunc(data_date) = date '2016-04-05'
group by trim(data_date);
gives results like:
347 05-APR-16
Why are the queries giving different results for the same day?
Because your man_date_sub values are not all at midnight. If you keep running the first query the number of records returned will (probably) gradually reduce. That is only happening to the count for the 5th as that is a week ago. Your sysdate - 7 is a moving target, not just as you move from day to day, but as time passes during the day.
You can check the times with:
select to_char(man_date_sub, 'YYYY-MM-DD HH24:MI:SS'),
to_char(sysdate - 7, 'YYYY-MM-DD HH24:MI:SS'),
man_date_sub - (sysdate - 7)
from man
where trunc(man_date_sub) = date '2016-04-05';
You'll see that some have times before the current sysdate time, while others have times after it. The third, generated, column will show some positive and some negative values.
In your second query you're comparing trunc(man_date_sub), which sets the time part to midnight, with date '2016-04-05', which is also at midnight; so all the records at any time on that day now match.
You can go back to midnight on your 7-day range, and get an equivalent result, by truncating sysdate:
select count(*), trim(man_date_sub)
from man
where man_status = 'SUBMITTED' and man_date_sub > trunc(sysdate)-7
group by trim(man_date_sub);
Your use of the trim() function is a bit odd; all you're doing is removing leading and trailing whitespace from the string '05-APR-16', which isn't actually doing anything. You're also relying on implcit conversion of the date to a string using your session NLS_DATE_FORMAT. It would be better to specify the format:
select count(*), to_char(man_date_sub, 'YYYY-MM-DD')
from man
where man_status = 'SUBMITTED' and man_date_sub > trunc(sysdate)-7
group by to_char(man_date_sub, 'YYYY-MM-DD');
If you ran your original query in a session that had an NLS_DATE_FORMAT that included time elements then you wouldn't get the result you expect.
I'm not sure if you're confusing it with trunc(), though clearly you're using that elsewhere. Truncating a date sets the time portion to midnight (by default; it can do other things), but leaves it as a date, which would be suitable for grouping but should still be formatted explicitly for display.
Related
I am trying to get records from 29th April,2022 on hourly basis from Oracle DB, however with the below query I am getting records count older than 29th April as well(all previous records count as well). Can you help fine tune the query?
SELECT DISTINCT
COUNT(*),
STATUS,
TO_CHAR(LOAD_DATE,'DD-MON-YY HH24')
FROM
TARGET_HIST
WHERE
STATUS = 'A'
AND TO_CHAR(LOAD_DATE, 'DD-MON-YY HH24:MI:SS') > '29-APR-22 00:00:00'
GROUP BY
STATUS,
TO_CHAR(LOAD_DATE,'DD-MON-YY HH24')
ORDER BY
STATUS,
TO_CHAR(LOAD_DATE,'DD-MON-YY HH24');
Try this. Since you didn't provide any sample data I didn't test it for you
select trunc(load_date,'HH') "HOUR", count(*)
from target_hist
where status='A' AND
load_date between to_date('29/04/2022','DD/MM/YYYY') and to_date('29/04/2022 23:59:59','DD/MM/YYYY HH24:MI:SS');
Group by trunc(load_date,'HH')
Order by trunc(load_date,'HH')
Two problem with the same reason:
In your WHERE clause you look for rows after '29-APR-22 00:00:00', but you get rows before that.
In your ORDER BY clause you get the dates sorted in a mangled order.
This is because you have converted the datetimes to strings where '29-APR-22' comes after '01-MAY-22', but before '30-JAN-22', because '2' comes after '1' and before '3'.
If you want to sort and compare datetimes, then use datetimes. You can truncate them down to the hour with TRUNC(load_date, 'hh').
select
trunc(load_date, 'hh') as load_hour,
status,
count(*)
from target_hist
where status = 'A'
and load_date >= date '2022-04-29'
group by trunc(load_date, 'hh'), status
order by trunc(load_date, 'hh'), status;
Leave it to your app to display the datetime in the format the user wants to see it. If you need a particular format, e.g. for exporting the data into a file, you can apply TO_CHAR on the truncated datetime TO_CHAR(trunc(load_date, 'hh'),'DD-MON-YY HH24') in the select clause (and only there).
Please note that I have removed DISTINCT from the query, because there are no duplicates to remove. And I am using a date literal in the WHERE clause. And >=in order to include midnight.
This query considers all days since April 29. If you want this day only, then add and load_date < date '2022-04-30'.
Running below query and not getting the output. Can someone please tell whats wrong in it?
Select distinct (table.datex)
from table
where table.datex =
(
CASE when extract( day from sysdate) >=19
then last_day(add_months(sysdate, -1))
else last_day(add_months(sysdate, -2))
END
)
Sample data
Datex
ID
30-JUN-21
A
31-MAY-21
B
29-JUN-21
C
Expected result
Datex
30-JUN-21
When I am passing the value hard-coded(calculated by the case) to where clause it's working fine, but when I apply the case it's not working. No error. No output is coming.
Date or datetime?
Oracle's LAST_DAY doesn't do what the name suggests, and the docs (https://docs.oracle.com/en/database/oracle/oracle-database/21/sqlrf/LAST_DAY.html#GUID-296C7C02-7FB9-4AAC-8927-6A79320CE0C6) fail to explain that, too.
Unlike several other DBMS Oracle doesn't have a date type. It only has a datetime type and they even call that inappropriately DATE. This means that a "date" in Oracle always has a time part. A date with its time part set to 00:00:00 can be considered a day's midnight (i.e. the very beginning of the day) or the whole day.
The function SYSDATE gives us a date in the sense of the DATE datatype, not in the sense of a real day, i.e. it gives us the datetime of "now", e.g. 2021-07-20 14:38:00. ADD_MONTHS changes the month in that datetime (and sometimes the year and sometimes even the day), i.e. leaves the time part untouched. LAST_DAY, too, changes the date part to get to the last day of the month, but leaves the time part untouched.
Your CASE expression hence results in something like TIMESTAMP '2021-07-20 14:38:00' and not in DATE '2021-07-20' as one might expect.
You say that you tried your query with the date you computed wth your case expression, and it worked. Did you compute the resulting day in your head or with a query? If the latter: The tool you are using may be set to only display a datetime's date part and omit the time part. This would explain why you only saw 30-JUN-21 when checking the CASE expression.
Solution
Truncate the datetime down to a whole day
Select distinct datex
from mytable
where (extract(day from sysdate) >=19 and datex = trunc(last_day(add_months(sysdate, -1))))
or (extract(day from sysdate) < 19 and datex = trunc(last_day(add_months(sysdate, -2))))
It doesn't matter whether you apply TRUNC late as in my example or right away on SYSDATE (with TRUNC(SYSDATE)) by the way. The only aim is to get rid of the time part at some point in the expression.
Don't use case in where clauses. Boolean logic can handle that.
And take a look if it is really the condition you want
Select distinct datex
from your_table
where
(
extract(day from sysdate) >=19
and datex = last_day(add_months(sysdate,-1))
)
or
(
extract(day from sysdate) < 19
and datex = last_day(add_months(sysdate,-2))
)
I need to analyze an SQL query (and construct its equivalent in MDX). I'm not familiar with SQL and can't access the database, so there are 5 simple things I can't figure out:
What does the part WHERE idate BETWEEN trunc(SYSDATE, 'iw')-7 AND trunc(SYSDATE, 'iw')-3 mean? Specifically:
What does subtracting 7 from trunc(SYSDATE, 'iw') do? Subtract 7 weeks or 7 days? I understand the trunc(...) expression is a value 0-53 corresponding to the week of the year, but it seems to clash with the label "previous week" and stated purpose of the query.
How does SQL compare dates? Are the values from trunc(...) evaluated as dates during comparison?
The query seems to group rows together if they happened in the same minute. However, the few rows of output I can see have 10-minute granularity (00:00, 00:10, 00:20, etc.) Is there something in the query that groups rows into 10 minute intervals, or is this a result of the input data?
Why are calls to substr() and to_char() and needed in the group by condition? What would happen if trunc(idate, 'HH24:MI') was used instead?
What does the pm do? There is also a cm that seems to have a similar function. Are these part of the temporary table names?
Finally, how do the hash marks (#) affect this query? I read it might be to signify temporary tables. If so, are these temporary tables created manually, or does something in the query cause them to be created?
For reference here is the query. (On a Oracle database, if it makes any difference.) Its purpose is to "analyze how firewall accept events are trending compared to last week":
SELECT 'Previous Week Average' AS term ,
Substr(To_char(idate, 'HH24:MI'), 0, 4)
|| '0' AS event_time ,
Round(Avg(tot_accept)) AS cnt
FROM (
SELECT *
FROM st_event_100_#yyyymm-1m#
WHERE idate BETWEEN trunc(SYSDATE, 'iw')-7 AND trunc(SYSDATE, 'iw')-3 #stat_monitor_group_query#
UNION ALL
SELECT *
FROM st_event_100_#yyyymm#
WHERE idate BETWEEN trunc(SYSDATE, 'iw')-7 AND trunc(SYSDATE, 'iw')-3 #stat_monitor_group_query# ) pm
GROUP BY substr(to_char(idate, 'HH24:MI'), 0, 4)
|| '0'
UNION ALL
SELECT 'Today' AS term ,
substr(to_char(idate, 'HH24:MI'), 0, 4)
|| '0' AS event_time ,
round(avg(tot_accept)) AS cnt
FROM st_event_100_#yyyymm# cm
WHERE idate >= trunc(SYSDATE) #stat_monitor_group_query#
GROUP BY substr(to_char(idate, 'HH24:MI'), 0, 4)
|| '0'
ORDER BY term DESC,
event_time ASC
iw truncates the date to the first day of the calendar week as defined by the ISO 8601 standard, which is Monday. When you subtract numbers from the date, it is always the number of days. So, idate BETWEEN trunc(SYSDATE, 'iw')-7 AND trunc(SYSDATE, 'iw')-3 gives you those dates that fall between previous week's Monday and Friday.
to_char(idate, 'HH24:MI') gives you the time(hour and minute) part in 24hr format. Ex: 14:33. By using substrin to extract only 4 characters, you are actually getting 14:3. So yes, this groups with a granularity of 10 mins.
You cannot write trunc(idate, 'HH24:MI'). It can only have 1 precision specifier.
If you write trunc(idate,'HH24'), it truncates to the hour. If you use MI, it truncates to the minute. So, to truncate it to 10 mins is a little tricky.
pm is just an alias for the whole subquery.
SELECT *
FROM st_event_100_#yyyymm-1m#
......
WHERE idate BETWEEN trunc(SYSDATE, 'iw')-7 AND trunc(SYSDATE, 'iw')-3 #stat_monitor_group_query#
# is part of the table anme in your query. It has no significance as such. But, it might be project/company specific.
I need to get the difference of 2 date fields, if the greater date is null then I'll use SYSDATE instead. Having this requirement, I created a function to solve this issues (note: this code follows the standard of the organization, not my personal taste)
CREATE FUNCTION F_GET_DIFFERENCE (P_WORKFLOWID NUMBER)
RETURN NUMBER --result in minutes
IS
TIME NUMBER;
BEGIN
TIME := 0
SELECT
F_WORKTIME_DIFF(NVL(X.ENDDATE, SYSDATE), X.STARTDATE)
INTO
TIME
FROM
TABLEX X
WHERE
X.WORKFLOWID = P_WORKFLOWID;
RETURN TIME;
EXCEPTION
WHEN OTHERS THEN
RETURN 0;
END;
The F_WORKTIME_DIFF function already exists and calculates the worktime of the day (assumming nobody works at 12 a.m. and things like that). The problem is when calling this function, the result contains an additional amount of time. That's very strange, because when executing the query in the function, it returns the expected output.
Example (important: date format in Peru is DD/MM/YYYY HH24:MI:SS)
TABLEX
WORKFLOWID STARTDATE ENDDATE
1 '01/12/2012 10:00:00' null
Assumming that the server day is the same day (01/12/2012) but greater time (10:01:00), we execute the function:
SELECT F_GET_DIFFERENCE(1)
FROM DUAL;
The result is: 14.
Now, executing the query in the function and having the server time at 10:02:00, the result is 2 (exact output).
I even tried executing this
SELECT
F_WORKTIME_DIFF(NVL(X.ENDDATE, SYSDATE), X.STARTDATE) SELECT_WAY,
F_GET_DIFFERENCE(1) FUNCTION_WAY
FROM
TABLEX X
WHERE
X.WORKFLOWID = 1
And the result is (having the server time at 10:10:00)
SELECT_WAY FUNCTION_WAY
10 24
Is maybe any consideration that I must take into account when working with Oracle dates in inner functions or anything that could explain this odd behavior?
It is difficult to tell anything without seeing the function F_WORKTIME_DIFF.
Whatever is the datatype returned from F_WORKTIME_DIFF, it is casted to number when assigned to the variable time. This may be a clue.
This may not be exactly what are you looking for but the first example gives you hours diff between two dates:
Select EXTRACT(HOUR FROM (SYSDATE - trunc(SYSDATE )) DAY TO SECOND ) From dual
/
Select
EXTRACT(hour From Cast(SYSDATE as timestamp)) hh,
EXTRACT(minute From Cast(SYSDATE as timestamp)) mi,
EXTRACT(second From Cast(SYSDATE as timestamp)) ss
From dual
/
I need to find some records created in a range of quarters. For example, I'm looking for all records created between the 4th quarter of 2008 and the 1st quarter of 2010. I have this in my WHERE-clause:
...and r.record_create_date between to_date('2008 4','YYYY Q')
and to_date('2010 1','YYYY Q')
but Oracle says: ORA-01820: format code cannot appear in date input format. The Q is a valid date format symbol, so I'm not sure what's happened. Is this even a valid way to find values in between calender quarters, or is there a better way?
Also interesting, and possibly related, if I execute this:
select to_date('2009','YYYY') from dual;
The value displayed in my IDE is 2009-08-01. I would have expected 2009-08-04, since today is 2010-08-04.
This:
select to_date('2009 1','YYYY Q') from dual;
of course, fails.
(Oracle 10g)
Oracle says: ORA-01820: format code cannot appear in date input format. The Q is a valid date format symbol, so I'm not sure what's happened.
See the second column of table 2.15 at http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/sql_elements004.htm#i34948. Not all format elements are allowed when converting to dates, timestamps, etc.
I recommend against using between for date range checks. People often will miss values within the ending day that the expect to be included. So I would translate:
and r.record_create_date between to_date('2008 4','YYYY Q')
and to_date('2010 1','YYYY Q')
To
and to_date('2008-10-01', 'YYYY-MM-DD') <= r.record_create_date
and record_create_date < to_date('2010-04-01', 'YYYY-MM-DD') -- < beginning of 2Q2010.
Someone asked the same question on OTN: http://forums.oracle.com/forums/thread.jspa?threadID=1081398&tstart=255
The crux of the issue is that you can not specify "Q" in the TO_DATE function.
Given that you're already specifying a portion of the date, why not provide the entire date? Mind too that to_date('2010 1','YYYY Q') would give you Jan 1st, 2010 when you really want March 31st, 2010... at a second to midnight.
Since the relationship between quarters to months is one-to-many, it doesn't make sense to do TO_DATE('2008 1', 'yyyy q'); what date should be returned? The first of the quarter, the end of the quarter, ...? (On the other hand, converting a date to a quarter - like TO_CHAR(SYSDATE, 'yyyy q') makes sense because a specific date only exists in one quarter.)
So, if you do want a query that looks for a date that falls between two quarters, you will have to "rolll your own" (explicitly stating the dates of the start/end of a quarter.)
As a side note, in case anyone is considering not using TO_DATE please do not use things like: WHERE date_value BETWEEN 'date string1' and 'date string2' without the TO_DATE function. It assumes a default date format and under certain situations can avoid potentially useful indexes altogether.
Below is one example where the same query can have a different result.
select sysdate from dual where sysdate between '1-Jan-10' and '31-Dec-10';
SYSDATE
---------
04-AUG-10
SQL> alter session set nls_date_format = 'YYYY-MM-DD';
Session altered.
SQL> select * from dual where sysdate between '1-Jan-10' and '31-Dec-10';
no rows selected
(Notice that in the second instance no error is returned. It just assumes Jan 10, 0001 and Dec. 10th, 0031.)
I think the best way is to just input the quarter start date and quarter end dates without even bothering with to_date. I think if you use
between '1-Jan-10' and '31-Dec-10'
for example, then you don't (in Oracle I believe) need to_date and it isn't much more difficult than typing in the quarter number
To calculate in Oracle the first day of a quarter and the last day of a quarter from the year and quarter:
I Use the fact
start_month= -2 + 3 * quarter
last_month = 3 * quarter
variable v_year number
variable v_quarter number
exec :v_year :=2017
exec :v_quarter:=4
select :v_year as year,
:v_quarter as quarter,
to_date(:v_year||to_char(-2+3*:v_quarter,'fm00'),'yyyymm') as quarter_start,
last_day(to_date(:v_year||to_char(3*:v_quarter,'fm00')||'01 23:59:59','yyyymmdd hh24:mi:ss')) as quarter_end
from dual a;
YEAR|QUARTER|QUARTER_START |QUARTER_END
2017| 4|2017-10-01 00:00:00|2017-12-31 23:59:59