Increase row number every time a flag changes - oracle11g

I have gone through a similar post in Stack overflow...
but my query is :
If my table generates a flag in run time execution,then how can I increase Grp_number(generate run time) every time my flag changes.
my Oracle query:
Select emp_id,
Case when MOD(rownum/3)=1 and rownum>1 then 'Y' else 'N' as flag
from Transaction_table
Desired o/p Data format:
emp_id Flag GRP_number
1 N 1
2 N 1
3 N 1
4 Y 2
5 N 2
6 N 2
7 Y 3

You cannot reference a column in another column in the same select list. You need to use sub query to avoid INVALID IDENTIFIER error.
Do it like -
WITH DATA AS(
SELECT emp_id,
CASE
WHEN MOD(rownum/3)=1
AND rownum >1
THEN 'Y'
ELSE 'N' AS flag
FROM Transaction_table
)
SELECT emp_id, flag, SUM(gap) over (PARTITION BY person
ORDER BY DAY) grp
FROM(
SELECT emp_id, flag,
CASE WHEN flag = lag(flag) over (PARTITION BY person
ORDER BY DAY)
THEN 0
ELSE 1
END gap
FROM DATA)

Related

case statement inside nested case

I will make this question as more precise
I have this data
id product count
1 a 10
1 b 20
1 c 10
1 d 30
I want the result like
Since both product A and B has values i want to count them as one so the result should count(distinct A,C,D) that is 3
If any of product that is (A has values but B does not or vice versa ) then also the result has to be 3
in case both product A and B does not have value then the result should be 2
how to achieve this by using a case statement in oracle plsql
I'm not sure how you define either count of a or either count of b not both, but if you defined it explicitly then you can try this one:
with t as (
select 1 as id, 'a' as product from dual
union all
select 1 as id, 'b' as product from dual
union all
select 1 as id, 'c' as product from dual
union all
select 1 as id, 'd' as product from dual
) select id,
product,
count( case when product in ('c', 'd', 'a') then 1 end ) --change 'a' to 'b' to get the the result for 'b'
from t
group by id, product;

Oracle Timestamp based calculation on every day using Two datetime column

I have a table that contains two time stamp t1(event open date) and t2(event close date) and a primary key eventid.
If event is open then t2 will be null whenever even gets closed the same row will be get updated with event closure date t2.
For example I want to check how many issues are open on every day bases on opened date (t1) from 01-apr-2016 to 10-apr-2016.
I have to calculate how many events are open for every day based on a selected date range.
Lets say if eventid 1 has got opened on 1st-APR and got closed on 10th-APR and I am calculating the number of opened issues for every day on 11th-APR then it should give me number of open event 1 from 1st-APR to 10th-APR.
Table Structure:-
================================================
EVENTID T1 T2
================================================
1 01-apr-2016 10-apr-2016
2 02-apr-2016 08-apr-2016
3 05-apr-2016 09-apr-2016
Expected Output:-
==============================================================================
DATE TOTAL_OPEN_EVENTS
==============================================================================
01-apr-2016 1
02-apr-2016 2(1 issue open on 1st(not closed on 2nd) and 1 on 2nd)
03-apr-2016 2
04-apr-2016 2
05-apr-2016 3
06-apr-2016 3
07-apr-2016 3
08-apr-2016 2(1 issue got closed on 8th(which was opened on 2nd))
09-apr-2016 2
10-apr-2016 0
How to do this kind of calculation in Oracle database ?
In order to generate the end report, you need a row for each date in your desired range. You could either use a calendar table, if available, or I find using a query on DUAL using CONNECT BY LEVEL < some_number works well to generate rows on the fly. (In this case "some_number" will be the number of days you want to report on.)
From there, you just need to join the individual dates to the date ranges in your event table:
-- create table "events" table
create table event_date_ranges
as
select 1 as event_id, TO_DATE('2016-APR-01', 'YYYY-MM-DD') as start_date, TO_DATE('2016-APR-10', 'YYYY-MON-DD') as end_date from dual
union all
select 2 as event_id, TO_DATE('2016-APR-02', 'YYYY-MM-DD') as start_date, TO_DATE('2016-APR-08', 'YYYY-MON-DD') as end_date from dual
union all
select 3 as event_id, TO_DATE('2016-APR-05', 'YYYY-MM-DD') as start_date, TO_DATE('2016-APR-09', 'YYYY-MON-DD') as end_date from dual
;
with
date_range_qry as
(-- one way to set the start and end dates for your report
select TO_DATE('2016-APR-01', 'YYYY-MM-DD') as report_start_date
, TO_DATE('2016-APR-10', 'YYYY-MM-DD') as report_end_date
from dual
)
, dates_qry
as
(
-- generate a row for all dates between 2016-APR-01 and 2016-APR-10
select report_start_date + ROWNUM - 1 as report_date
from dual
cross join
date_range_qry drq
connect by level <= (drq.report_end_date - drq.report_start_date + 1)
)
select dq.report_date, count(edr.event_id) as total_open_events
from dates_qry dq
left outer join
event_date_ranges edr
on dq.report_date >= edr.start_date
and dq.report_date < edr.end_date
group by dq.report_date
order by dq.report_date
Output:
REPORT_DATE TOTAL_OPEN_EVENTS
2016-APR-01 1
2016-APR-02 2
2016-APR-03 2
2016-APR-04 2
2016-APR-05 3
2016-APR-06 3
2016-APR-07 3
2016-APR-08 2
2016-APR-09 1
2016-APR-10 0
You can try this:
create table events_log
as
select 1 as event_id, TO_DATE('01-04-2016', 'DD/MM/YYYY') as T1, TO_DATE('10-04-2016', 'DD/MM/YYYY') as T2 from dual
union all
select 2 as event_id, TO_DATE('02-04-2016', 'DD/MM/YYYY') as T1, TO_DATE('08-04-2016', 'DD/MM/YYYY') as T2 from dual
union all
select 3 as event_id, TO_DATE('05-04-2016', 'DD/MM/YYYY') as T1, TO_DATE('09-04-2016', 'DD/MM/YYYY') as T2 from dual
;
--------------
select v.REPORT_DATE, count(t.EVENT_ID) as open_event
from events_log t,
(select to_date('01/04/2016', 'DD/MM/YYYY') + ROWNUM - 1 as report_date
from dual
connect by level <= (to_date('11/04/2016', 'DD/MM/YYYY') -
to_date('01/04/2016', 'DD/MM/YYYY') + 1)) v
where t.T1(+) <= v.report_date
and t.T2(+) >= v.report_date
group by v.report_date
order by v.report_date;
Output will be:
report_date open_event
01/04/2016 1
02/04/2016 2
03/04/2016 2
04/04/2016 2
05/04/2016 3
06/04/2016 3
07/04/2016 3
08/04/2016 3
09/04/2016 2
10/04/2016 1
11/04/2016 0

how update the second row in oracle11g?

I tried this request:
UPDATE studentTble e SET e.oStudent.oPerson.oAddr.city='UK' WHERE rownum = 2
ID NAME STREET CITY
100 --------Henrry.Student-----ST 17.---NY
101 --------Samm.Student-------ST 17D.--OR
102 --------Hanna.Student------ST 25D.--MX
WHERE rownum = 2
That is not how ROWNUM works. Rownum is not incremented to 2 unless Oracle assigns rownum to the first row. So, WHERE ROWNUM = 2 would return no rows, since rownum is never incremented beyond 1 in this case.
how update the second row in oracle11g?
There is nothing called a Nth row unless you have an ordered set of rows. In your case, if you have an explicit ORDER BY on ID column, by default in ascending order, then you could choose the second row from the sub-query.
UPDATE studenttble e
SET e.ostudent.operson.oaddr.city = 'UK'
WHERE id = (SELECT id
FROM (SELECT id,
ROWNUM rn
FROM (SELECT id,
ROWNUM rn
FROM studenttble
ORDER BY id))
WHERE rn = 2)
You could also use ANALYTIC ROW_NUMBER() to assign rank to each row ordered by ID column.

SQLite count(*) in while clause

I have a calendar table in which there are all the dates in the future and a workday field:
fld_date / fld_workday
2014-01-01 / 1
2014-01-02 / 1
2014-01-03 / 0
...
I want select a date which are n workday far from another date. I tried two ways, but i failed:
The 5th workday from 2014-11-07:
1.
SELECT n1.fld_date FROM calendar as n1 WHERE n1.fld_workday=1 AND
(select count(*) FROM calendar as n2 WHERE n2.fld_date>='2014-11-07' AND n2.fld_workday=1)=5
It gave back 0 row.
2.
SELECT fld_date FROM calendar WHERE fld_date>='2014-11-07' AND fld_workday=1 LIMIT 1 OFFSET 5
It's ok, but i would like to change the 5 days constant to a field, and it's cannot (it would be inside a bigger select statement):
SELECT fld_date FROM calendar WHERE fld_date>='2014-11-07' AND fld_workday=1 LIMIT 1 OFFSET fld_another_field
Any suggestion?
In the first query, the subquery does not refer to the row in n1.
You need a correlated subquery:
SELECT fld_Date
FROM Calendar AS n1
WHERE fld_WorkDay = 1
AND (SELECT COUNT(*)
FROM Calendar AS n2
WHERE fld_Date BETWEEN '2014-11-07' AND n1.fld_Date
AND fld_WorkDay = 1
) = 5
LIMIT 1
The subquery is extremly inefficient if there is no index on the fld_Date column.
You can avoid executing the subquery for every row in n1 by adding another condition with an estimate of the result date (assuming that there are between about four to five work days per week, and using a few extra days to be sure):
...
WHERE fldDate BETWEEN date('2014-11-07', (5 * 4/7 - 10) || ' days')
AND date('2014-11-07', (5 * 5/7 + 10) || ' days')
AND fldWorkDay = 1
AND (SELECT ...

SQLITE syntax error performing an Update

I'm trying to improve a transit scheduling table by adding a column and flagging some rows to indicate they are the last stop for each trip.
Each trip will have many rows showing its stops and their sequence along the trip. I want to update the LastStop column with a '1' if the Sequence number is the highest for that trip.
I think the following SQL is on the right track but I am getting a "no such column: s1.stop_sequence" so I have no idea if I'm even on the right track until this unobvious to me error is resolved. I am a SQL lightweight barely beyond novice level. Stop_Sequence is definitely the correct name for the column.
UPDATE stop_times
SET LastStop = '1'
WHERE stop_sequence =(
SELECT max(st.stop_sequence)
FROM stop_times s1
WHERE s1.trip_id = trip_id
)
AND
trip_id = s1.trip_id
AND
stop_ID = s1.stop_id;
A simplified version of sample data is below.
TripID Stop Sequence LastStop
665381 1766 1
665381 3037 2
665381 3038 3 1
667475 1130 1
667475 2504 2 1
644501 2545 1
644501 3068 2
644501 2754 3
644501 3069 4
644501 2755 5 1
You cannot refer to a column in the subquery from the outer query.
Furthermore, the filter trip_id = s1.trip_id is duplicated, and you do not want to filter on stop_id because that would prevent the MAX from looking at any other stops of the trip.
Try this:
UPDATE stop_times
SET LastStop = '1'
WHERE Stop_Sequence = (SELECT MAX(Stop_Sequence)
FROM stop_times s1
WHERE s1.Trip_ID = stop_times.Trip_ID)
Alternatively, a last stop is a stop for which no other stop with a larger sequence number in the same trip exists:
UPDATE stop_times
SET LastStop = '1'
WHERE NOT EXISTS (SELECT 1
FROM Stop_Sequence s1
WHERE s1.Trip_ID = stop_times.Trip_ID
AND s1.Stop_Sequence > stop_times.Stop_Sequence)
This will work for you, as long as stops field is always less than 1000 (use bigger multiplier if it is):
UPDATE stop_times
SET laststop = 1
WHERE tripid*1000+sequence IN (
SELECT tripid*1000+sequence FROM (
SELECT tripid, max(sequence) AS sequence
FROM stop_times
GROUP BY 1
)
)
I would have written this using tuple syntax, but SQLite does not support it:
UPDATE stop_times
SET laststop = 1
WHERE (tripid, sequence) IN (
SELECT (tripid, sequence) FROM (
SELECT tripid, max(sequence) AS sequence
FROM stop_times
GROUP BY 1
)
)
Sorry, no SQLFiddle - it does not seem to work for me today.

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