I am trying to find out average of electricity volume of certain day in a week with the following query:
SELECT avg(volume)
FROM v_nem_rm16
WHERE to_char(day, 'day') = 'monday';
where the v_nem_rm16 is a table and volume, day are its columns and my query is returning null whatever I change the day value 'monday', 'tuesday',....
is this query wrong?
Actually 'DAY' is returned with padding spaces on the right side.
If you use 'RTRIM' then you can avoid the null values.
SELECT avg(volume)
FROM v_nem_rm16
WHERE RTRIM(to_char(day, 'day')) = 'monday';
I would rather use different date format to_char DAY is nls-dependent that is bad (for instance your software will fail in Spain). D returns number so in your case the query should look like
SELECT avg(volume)
FROM v_nem_rm16
WHERE RTRIM(to_char(day, 'd')) = 1;
Related
I want to display the amount of data by month and year. This is an example of displaying data by date:
select count(*) from db.trx where trxdate = to_date('2018-04-23','yyyy-mm-dd')
When I try to display the amount of data by month and year, no query results appear. Is there something wrong with the query?
The query:
select count(*) from db.trx where trxdate = to_date('2018-04','yyyy-mm')
You need to apply the function to trxdate. Using your logic:
SELECT Count(*)
FROM olap.trxh2hpdam
WHERE To_char(trxdate, 'YYYY-MM') = '2018-04';
However, I strongly recommend that you use direct date comparisons:
WHERE trxdate >= date '2018-04-01'
AND
trxdate < date '2018-05-01'
This will allow the database to use an index on trxdate.
There are a couple of ways of accomplishing what you're trying to do. Which one works for you will depend on your database design (for example, the indexes you've created). One way might be this:
SELECT COUNT(*) FROM olap.trxh2hpdam
WHERE TRUNC(trxdate, 'MONTH') = DATE'2018-04-01';
This will round the date down to the first of the month (and, of course, remove any time portion). Then you simply compare it to the first of the month for which you want the data. However, unless you have an index on TRUNC(trxdate, 'MONTH'), this may not be the best course of action; if trxdate is indexed, you'll want to use:
SELECT COUNT(*) FROM olap.trxh2hpdam
WHERE trxdate >= DATE'2018-04-01'
AND trxdate < DATE'2018-05-01';
There are a number of functions at your disposal in Oracle (e.g. ADD_MONTHS()) in the event that the date you use in your query is supposed to be dynamic rather than static.
Just FYI, there is no reason not to use ANSI date literals when trying to retrieve data by day as well. I'm not sure your original query is a good example of getting data for a particular day, since the Oracle DATE datatype does at least potentially include a time:
SELECT COUNT(*) FROM olap.trxh2hpdam
WHERE trxdate >= DATE'2018-04-23'
AND trxdate < DATE'2018-04-24';
or:
SELECT COUNT(*) FROM olap.trxh2hpdam
WHERE TRUNC(trxdate) = DATE'2018-04-23';
EDIT
In case the month and year are dynamic, I would build a date from them (e.g., TO_DATE('<year>-<month>-01', 'YYYY-MM-DD')) and then use the following query:
SELECT COUNT(*) FROM olap.trxh2hpdam
WHERE trxdate >= TO_DATE('<year>-<month>-01', 'YYYY-MM-DD')
AND trxdate < ADD_MONTHS( TO_DATE('<year>-<month>-01', 'YYYY-MM-DD'), 1 );
Hope this helps.
I have a table A with startdate column which is TIMESTAMP WITHOUT TIME ZONE I need to write a query/function that generate a list of months from the MIN value of the column till MAX value of the column.
For example:
startdate
2014-12-08
2015-06-16
2015-02-17
will generate a list of: (Dec-14,Jan-15,Feb-15,Mar-15,Apr-15,May-15,Jun-15)
How do I do that? I never used PostgreSQL to generate data that wasn't there... it always has been finding the correct data in the DB... any ideas how to do that? Is it doable in a query?
For people looking for an unformatted list of months:
select * from generate_series('2017-01-01', now(), '1 month')
You can generate sequences of data with the generate_series() function:
SELECT to_char(generate_series(min, max, '1 month'), 'Mon-YY') AS "Mon-YY"
FROM (
SELECT date_trunc('month', min(startdate)) AS min,
date_trunc('month', max(startdate)) AS max
FROM a) sub;
This generates a row for every month, in a pretty format. If you want to have it like a list, you can aggregate them all in an outer query:
SELECT string_agg("Mon-YY", ', ') AS "Mon-YY list"
FROM (
-- Query above
) subsub;
SQLFiddle here
This question already has answers here:
Counting number of records hour by hour between two dates in oracle
(5 answers)
Closed 8 years ago.
I'm trying to get the number of records created each hour but running into trouble with getting the results to group correctly. The idea is similiar to: How to count number of records per day?
However, the field I'm using to Group by is a Date-time field that records down to the second. This seems to be causing trouble with the Group By statement, as when the query returns, there is one row for each second in the specified time period, which is way too much data and will make the work I want to do with the results more difficult than it needs to be (if for no other reason that it's too many rows to fit on one Excel sheet).
My current code is:
SELECT ASD, Count(ASD) Num_CR
From DB_Name.Table_Name fcr
Where trunc(fcr.ASD) > to_Char('31-DEC-2014')
And trunc(fcr.ASD) < to_Char('31-JAN-2015')
And fcr.Status_Code = 'C'
Group By ASD
Order By ASD;
I've tried changing the Group By to be trunc(ASD), but that results in Toad throwing this error: ORA-00979: not a GROUP BY expression.
Thanks in advance!
When you use aggregation anything in the select and order by clauses must match what's in the group by clause:
SELECT trunc(ASD,'hh'), Count(ASD) Num_CR
From DB_Name.Table_Name fcr
Where trunc(fcr.ASD) > to_date('31-DEC-2014')
And trunc(fcr.ASD) < to_date('31-JAN-2015')
And fcr.Status_Code = 'C'
Group By trunc(ASD,'hh')
Order By trunc(ASD,'hh');
When applied to a date, trunc will truncate to the day. To truncate to a different level, specify the format of the element you'd like to truncate to as the second argument (e.g. 'hh' will truncate to the hour; 'mm' will truncate to the month).
SELECT to_char(ASD,'DD-MM-YYYY HH'), Count(ASD) Num_CR
From DB_Name.Table_Name fcr
Where trunc(fcr.ASD) > to_Char('31-DEC-2014')
And trunc(fcr.ASD) < to_Char('31-JAN-2015')
And fcr.Status_Code = 'C'
Group By to_char(ASD,'DD-MM-YYYY HH')
Order By to_char(ASD,'DD-MM-YYYY HH');
Quick and dirty :)
First off, why are you doing to_char on something that's already a string? Secondly, why are you trying to compare something that's (presumably) a DATE column to a string? That way lies madness...
I think you're after something like:
SELECT trunc(ASD, 'hh') asd_hr, Count(ASD) Num_CR
From DB_Name.Table_Name fcr
Where trunc(fcr.ASD) > to_date('31/12/2014', 'dd/mm/yyyy')
And trunc(fcr.ASD) < to_date('31/01/2015', 'dd/mm/yyyy')
And fcr.Status_Code = 'C'
Group By trunc(ASD, 'hh')
Order By trunc(ASD, 'hh');
Also worth noting, did you mean to exclude the last day of January from your query? If so, then fine, but if not, then perhaps you should change it to to_date('01/02/2015', 'dd/mm/yyyy')
I would like to create a WHERE condition to return results where only 1 day has passed between two timestamps. I tried this:
SELECT * FROM RDMAVWSANDBOX.VwNIMEventFct
INNER JOIN VwNIMUserDim ON VwNIMUserDim.NIM_USER_ID = VwNIMEventFct.NIM_USER_ID
INNER JOIN rdmatblsandbox.TmpNIMSalesForceDB ON TmpNIMSalesForceDB.EMAIL = VwNIMUserDim.USER_EMAIL_ADDRESS
WHERE (CONTRACT_EFFECTIVE_DATE - EVENT_TIMESTAMP) =1
But the result was an error message "Invalid Operation On An ANSI DATETIME value".
I guess that, looking at the code now, Teradata has no way of knowing whether the "1" in "= 1" is a day, hour or year.
How would I select data where only 1 day has passed between CONTRACT_EFFECTIVE_DATE and EVENT_TIMESTAMP?
Same again for 2 days, and 3 days etc?
If both columns are DATEs you can use =1which means one day.
For Timestamps you need to tell what kind of interval you want:
WHERE (CONTRACT_EFFECTIVE_DATE - EVENT_TIMESTAMP) DAY = INTERVAL '1' DAY
But i'm not shure if this is what you really want, what's your definition of 1 day?
Edit:
Based on your comment the best way should be:
WHERE CAST(CONTRACT_EFFECTIVE_DATE AS DATE) - CAST(EVENT_TIMESTAMP AS DATE) = 1
This avoids dealing with INTERVAL arithmetic :-)
Not sure about Teradata, but I think most versions of SQL have built-in date math functions. In MSSQL for instance you could do this:
...
WHERE DATEDIFF(DAY, CONTRACT_EFFECTIVE_DATE, EVENT_TIMESTAMP) = 1
Or if you wanted to make sure 24 hours had passed you could do:
...
WHERE DATEDIFF(HOUR, CONTRACT_EFFECTIVE_DATE, EVENT_TIMESTAMP) = 1
Other SQL's have their own versions of this, and you may have to use 'D' or 'DD' instead of 'DAY' or something (and maybe 'HH' instead of 'HOUR' likewise).
I have a postgresql table userDistributions like this :
user_id, start_date, end_date, project_id, distribution
I need to write a query in which a given date range and user id the output should be the sum of all distributions for every day for that given user.
So the output should be like this for input : '2-2-2012' - '2-4-2012', some user id :
Date SUM(Distribution)
2-2-2012 12
2-3-2012 15
2-4-2012 34
A user has distribution in many projects, so I need to sum the distributions in all projects for each day and output that sum against that day.
My problem is what I should group by against ? If I had a field as date (instead of start_date and end_date), then I could just write something like
select date, SUM(distributions) from userDistributions group by date;
but in this case I am stumped as what to do. Thanks for the help.
Use generate_series to produce your dates, something like this:
select dt.d::date, sum(u.distributions)
from userdistributions u
join generate_series('2012-02-02'::date, '2012-02-04'::date, '1 day') as dt(d)
on dt.d::date between u.start_date and u.end_date
group by dt.d::date
Your date format is ambiguous so I guess while converting it to ISO 8601.
This is much like #mu's answer.
However, to cover days with no matches you should use LEFT JOIN:
SELECT d.d::date, sum(u.distributions) AS dist_sum
FROM generate_series('2012-02-02'::date, '2012-02-04'::date, '1 day') AS d(d)
LEFT JOIN userdistributions u ON d.d::date BETWEEN u.start_date AND u.end_date
GROUP BY 1