Last day of month joined to second table - sql

I need to get the last day of the previous month and then join this to another table to return the year/month column that the date relates to but I'm struggling to achieve what I want.
I have tried:
SELECT b.yrmonth, LAST_DAY(ADD_MONTHS(SYSDATE,-1)) DT
FROM dual a
INNER JOIN D_DAY b on DT = b.DT
The year month just returns everything in the table rather than just one row so any help would be much appreciated!

Your query is effectively:
SELECT b.yrmonth,
'some constant masking b.DT' DT
FROM dual a
INNER JOIN
D_DAY b
on ( b.DT = b.DT ) -- Always true
You do not need to join the DUAL table and need to filter your table in the WHERE clause.
If the DT date column has varying time components:
SELECT yrmonth, dt
FROM D_DAY
WHERE DT >= TRUNC(LAST_DAY(ADD_MONTHS(SYSDATE,-1)))
AND DT < TRUNC(SYSDATE,'MM');
(Which will allow the database to use indexes on the DT column)
or, if your DT column always has dates with the time component at midnight:
SELECT yrmonth, dt
FROM D_DAY
WHERE DT = TRUNC(LAST_DAY(ADD_MONTHS(SYSDATE,-1)));

You don't need to join with dual table. You can simply add your condition in thewhere clause:
select *
from D_DAY b
where TRUNC(b.DT) = TRUNC(LAST_DAY(ADD_MONTHS(SYSDATE,-1))
and cast the date (with time) as date because LAST_DAY function returns date (with time component and if you want to check the date, you need to cast it before.

Related

SQL Union as Subquery to create Date Ranges from Start Date

I have three tabels, each of them has a date column (the date column is an INT field and needs to stay that way). I need a UNION accross all three tables so that I get the list of unique dates in accending order like this:
20040602
20051215
20060628
20100224
20100228
20100422
20100512
20100615
Then I need to add a column to the result of the query where I subtract one from each date and place it one row above as the end date. Basically I need to generate the end date from the start date somehow and this is what I got so far (not working):
With Query1 As (
Select date_one As StartDate
From table_one
Union
Select date_two As StartDate
From table_two
Union
Select date_three e As StartDate
From table_three
Order By Date Asc
)
Select Query1.StartDate - 1 As EndDate
From Query1
Thanks a lot for your help!
Building on your existing union cte, we can use lead() in the outer query to get the start_date of the next record, and withdraw 1 from it.
with q as (
select date_one start_date from table_one
union select date_two from table_two
union select date_three from table_three
)
select
start_date,
dateadd(day, -1, lead(start_date) over(order by start_date)) end_date
from q
order by start_date
If the datatype the original columns are numeric, then you need to do some casting before applying date functions:
with q as (
select cast(cast(date_one as varchar(8)) as date) start_date from table_one
union select cast(cast(date_two as varchar(8)) as date) from table_two
union select cast(cast(date_three as varchar(8)) as date) from table_three
)
select
start_date,
dateadd(day, -1, lead(start_date) over(order by start_date)) end_date
from q
order by start_date

map/sample timeseries data to another timeserie db2

I am trying to combine the results of two SQL (DB2 on IBM bluemix) queries:
The first query creates a timeserie from startdate to enddate:
with dummy(minute) as (
select TIMESTAMP('2017-01-01')
from SYSIBM.SYSDUMMY1 union all
select minute + 1 MINUTES
from dummy
where minute <= TIMESTAMP('2018-01-01')
)
select to_char(minute, 'DD.MM.YYYY HH24:MI') AS minute
from dummy;
The second query selects data from a table which have a timestamp. This data should be joined to the generated timeseries above. The standalone query is like:
SELECT DISTINCT
to_char(date_trunc('minute', TIMESTAMP), 'DD.MM.YYYY HH24:MI') AS minute,
VALUE AS running_ct
FROM TEST
WHERE ID = 'abc'
AND NAME = 'sensor'
ORDER BY minute ASC;
What I suppose to get is a query with one result with contains of two columns:
first column with the timestamp from startdate to enddate and
the second with values which are sorted by there own timestamps to the
first column (empty timestamps=null).
How could I do that?
A better solution, especially if your detail table is large, is to generate a range. This allows the optimizer to use indices to fulfill the bucketing, instead of calling a function on every row (which is expensive).
So something like this:
WITH dummy(temporaer, rangeEnd) AS (SELECT a, a + 1 MINUTE
FROM (VALUES(TIMESTAMP('2017-12-01'))) D(a)
UNION ALL
SELECT rangeEnd, rangeEnd + 1 MINUTE
FROM dummy
WHERE rangeEnd < TIMESTAMP('2018-01-31'))
SELECT Dummy.temporaer, AVG(Test.value) AS TEXT
FROM Dummy
LEFT OUTER JOIN Test
ON Test.timestamp >= Dummy.temporaer
AND Test.timestamp < Dummy.rangeEnd
AND Test.id = 'abc'
AND Test.name = 'text'
GROUP BY Dummy.temporaer
ORDER BY Dummy.temporaer ASC;
Note that the end of the range is now exclusive, not inclusive like you had it before: you were including the very first minute of '2018-01-31', which is probably not what you wanted. Of course, excluding just the last day of a month also strikes me as a little strange - you most likely really want < TIMESTAMP('2018-02-01').
found a working solution:
with dummy(temporaer) as (
select TIMESTAMP('2017-12-01') from SYSIBM.SYSDUMMY1
union all
select temporaer + 1 MINUTES from dummy where temporaer <= TIMESTAMP('2018-01-31'))
select temporaer, avg(VALUE) as text from dummy
LEFT OUTER JOIN TEST ON temporaer=date_trunc('minute', TIMESTAMP) and ID='abc' and NAME='text'
group by temporaer
ORDER BY temporaer ASC;
cheers

How to JOIN two columns of same table with different filters?

I want to join two columns of same table in following way...
QUERY 1 :
SELECT MRCY,DT FROM BILLING WHERE BILL_DATE='01-SEP-14' ORDER BY MRCY;
QUERY 2 :
SELECT DT "OLD DT" FROM BILLING WHERE BILL_DATE='01-AUG-14' ORDER BY MRCY;
How to join output of these query as single result set in Oracle database?
I mean columns should apear as follows:
MRCY DT OLD DT
You may want the following:
SELECT MRCY,
MAX(CASE WHEN BILL_DATE = DATE '2014-09-01' THEN DT END) as DT,
MAX(CASE WHEN BILL_DATE = DATE '2014-08-01' THEN DT END) as OLD_DT,
FROM BILLING
WHERE BILL_DATE IN (DATE '2014-09-01', DATE '2014-08-01')
GROUP BY MRCY
ORDER BY MRCY;
Just use UNION or UNION ALL. Union would remove the duplicates.
But, why would you do that? You can have both filters in the same query.
SELECT MRCY , DT
FROM BILLING
WHERE BILL_DATE IN (to_date('01-SEP-2014', 'DD-MON-YYYY'),
to_date('01-AUG-14', 'DD-MON-YYYY')
ORDER BY MRCY;
Internally, it will be rewritten as an OR logic.
Also, note that you are using literal instead of date. And that is incorrect way of dealing with dates. Oracle would do an implicit data conversion. You must always use TO_DATE.
And, an year should always be YYYY and not just YY. Aren't you aware of the Y2K bug?
SELECT MRCY, :new_dt as DT, :old_dt "OLD_DT"
FROM BILLING WHERE BILL_DATE IN (:new_dt, :old_dt)
ORDER BY MRCY;

Query for dates which are not present in a table

Consider a table ABC which has a column of date type.
How can we get all the dates of a range (between start date and end date) which are not present in the table.
This can be done in PLSQL.I am searching a SQL query for it.
You need to generate the arbitrary list of dates that you want to check for:
http://hashfactor.wordpress.com/2009/04/08/sql-generating-series-of-numbers-in-oracle/
e.g.:
-- generate 1..20
SELECT ROWNUM N FROM dual
CONNECT BY LEVEL <= 20
Then left join with your table, or use a where not exists subquery (which will likely be faster) to fetch the dates amongst those you've generated that contains no matching record.
Assuming that your table's dates do not include a time element (ie. they are effectively recorded as at midnight), try:
select check_date
from (select :start_date + level - 1 check_date
from dual
connect by level <= 1 + :end_date - :start_date) d
where not exists
(select null from mytable where mydate = check_date)
Given a date column in order to do this you need to generate a list of all possible dates between the start and end date and then remove those dates that already exist. As Mark has already suggested the obvious way to generate the list of all dates is to use a hierarchical query. You can also do this without knowing the dates in advance though.
with the_dates as (
select date_col
from my_table
)
, date_range as (
select max(date_col) as maxdate, min(date_col) as mindate
from the_dates
)
select mindate + level
from date_range
connect by level <= maxdate - mindate
minus
select date_col
from the_dates
;
Here's a SQL Fiddle
The point of the second layer of the CTE is to have a "table" that has all the information you need but is only one row so that the hierarchical query will work correctly.

Spread a table in a date time interval

Hello everyone it's been some days that I use sql to make analysis and I meet all kinds of problems that I solves thanks to your forum.
Now I'd like to create a view that recuperates the interval of time and shows in detail the dates in this interval.
I have the following table:
And I want to create the view that displays the result:
For example in the player1 MyTable to play five days from 01/01/2012
to 05/01/2012. So the view displays 5 lines for player1 with the date 01/01/2012, 02/01/2012, 03/01/2012, 04/01/2012, 05/01/2012.
Thank you in advance for your help.
You have to create a common table expression that give you the date range ( i have created a date range of the current month but you can choice another range) :
WITH DateRange(dt) AS
(
SELECT CONVERT(datetime, '2012-01-01') dt
UNION ALL
SELECT DATEADD(dd,1,dt) dt FROM DateRange WHERE dt < CONVERT(datetime, '2012-01-31')
)
SELECT dates.dt AS DatePlaying, PlayerName
FROM MyTable t
JOIN DateRange dates ON dt BETWEEN t.BeginDate AND t.DateEnd
ORDER BY PlayerName, DatePlaying
Another approach to this is simply to create an enumeration table to add values to dates:
with enumt as (select row_number() over (order by (select NULL)) as seqnum
from mytable
)
select dateadd(d, e.seqnum, mt.DateBegin) as DatePlaying, mt.PlayerName
from MyTable mt join
enum e
on enumt.seqnum <= e.NumberOfPlayingDay
The only purpose of the "with" clause is to generate a sequence of integers starting at 1.