I have a table with 4 columns, id, Stream which is text, Duration (int), and Timestamp (datetime). There is a row inserted for every time someone plays a specific audio stream on my website. Stream is the name, and Duration is the time in seconds that they are listening. I am currently using the following query to figure up total listen hours for each week in a year:
SELECT YEARWEEK(`Timestamp`), (SUM(`Duration`)/60/60) FROM logs_main
WHERE `Stream`="asdf" GROUP BY YEARWEEK(`Timestamp`);
This does what I expect... presenting a total of listen time for each week in the year that there is data.
However, I would like to build a query where I have a result row for weeks that there may not be any data. For example, if the 26th week of 2006 has no rows that fall within that week, then I would like the SUM result to be 0.
Is it possible to do this? Maybe via a JOIN over a date range somehow?
The tried an true old school solution is to set up another table with a bunch of date ranges that you can outer join with for the grouping (as in the other table would have all of the weeks in it with a begin / end date).
In this case, you could just get by with a table full of the values from YEARWEEK:
201100
201101
201102
201103
201104
And here is a sketch of a sql statement:
SELECT year_weeks.yearweek , (SUM(`Duration`)/60/60)
FROM year_weeks LEFT OUTER JOIN logs_main
ON year_weeks.yearweek = logs_main.YEARWEEK(`Timestamp`)
WHERE `Stream`="asdf" GROUP BY year_weeks.yearweek;
Here is a suggestion. might not be exactly what you are looking for.
But say you had a simple table with one column [year_week] that contained the values of 1, 2, 3, 4... 52
You could then theoretically:
SELECT
A.year_week,
(SELECT SUM('Duration')/60/00) FROM logs_main WHERE
stream = 'asdf' AND YEARWEEK('TimeStamp') = A.year_week GROUP BY YEARWEEK('TimeStamp'))
FROM
tblYearWeeks A
this obviously needs some tweaking... i've done several similar queries in other projects and this works well enough depending on the situation.
If your looking for a one table/sql based solution then that is deffinately something I would be interested in as well!
Related
edited as requested:
My apologies. I've been dealing with this a bit and it's well and truly in my head, but not for the reader.
We have multiple records in table A which have multiple entries in the Period column. Say it's like a football schedule. Teams will have multiple dates/times in the Period column.
When we run query:
We want records selected for the most recent games only.
We don't want the earlier games.
We don't want the games "scheduled" and not yet played.
"Last game played" i.e. Period for teams are often on different days.
Table like:
Team Period
Reds 2021020508:00
Reds 2021011107:00
City 2021030507:00
Reds 2021032607:00
City 2021041607:00
Reds 2021050707:00
When I run query, I want to see the records for last game played regardless of date. So if I run the query on 27 Mar 2021, I want:
City 2021030507:00
Reds 2021032607:00
Keep in mind I used the above as an easily understandable example. In my case I have 1000s of "Teams" each of which may have 100+ different date entries in the Period column and I would like the solution to be applicable regardless of number of records, dates, or when the query is run.
What can I do?
Thanks!
So this gives you your desired output using the sample data, does it fulfil your requirement?
create table x (Team varchar(10), period varchar(20))
insert into x values
('Reds','2021020508:00'),
('Reds','2021011107:00'),
('City','2021030507:00'),
('Reds','2021032607:00'),
('City','2021041607:00'),
('Reds','2021050707:00')
select Team, Max(period) LastPeriod
from x
where period <=Format(GetDate(), 'yyyyMMddhh:mm')
group by Team
The string-formatted date you have order by text, so I think this would work
SELECT TOP 2 *
FROM tableA
WHERE period = FORMAT( GETDATE(), 'yyyyMMddhh:mm' )
ORDER BY period
Perhaps you want:
where period = (select max(t2.period) from t t2)
This returns all rows with the last period in the table.
Using Teradata SQL Assistant, I want to be able to pull a table a year ahead but only the ones that would match the results in the query from the year before. Here's what I am trying to do. I pulled a table that contains information where the results in a specific column equals 0 for no. I want to pull information from 1 year ahead where the results in that column equals 1 but only include the account numbers that came when I pulled the results for the year before. Like only pull the customer account numbers for the year ahead that are the same from the year before.
Explanation: I pull the one table that has 0 in the column. From that, I want to see which of those accounts became a 1 in the table from a year ahead. The table has millions of accounts and I just have my settings for 10,000 of them so I want to see of those 10,000 in the first year that did not have the product, how many of them became 1 in the second year.
Can I do this? If so, how? I have been googling and I do not think I am explaining what I am trying to do correctly in my google query so I am coming up short with results.
Thanks for clarifying. That makes it a little simpler. I would put the second year data in a subquery and filter the main table on the first year and quantity = 0. This will give you two columns one with the first year and one with the second year. If you're only looking for this information for a single product_id you will need to add this to both WHERE clauses.
SELECT TABLE_NAME.ACCOUNT_ID, TABLE_NAME.QUANTITY AS "2019" , YEAR_TWO.QUANTITY AS "2020"
FROM TABLE_NAME
LEFT JOIN
(
SELECT *
FROM TABLE
WHERE YEAR = 2020
) YEAR_TWO ON TABLE_NAME.ACCOUNT_ID = YEAR_TWO.ACCOUNT_ID
WHERE TABLE_NAME.YEAR = 2019
AND TABLE_NAME.QUANTITY = 0
If you want just the % of accounts that are no longer 0 in the second year you could try something like this (adding up all the 1s and dividing by total count)
SELECT TABLE_NAME.YEAR, SUM(YEAR_TWO.QUANTITY) / COUNT(YEAR_TWO.QUANTITY) AS PERCENTAGE_NOT_ZERO
FROM TABLE_NAME
LEFT JOIN
(
SELECT *
FROM TABLE
WHERE YEAR = 2020
) YEAR_TWO ON TABLE_NAME.ACCOUNT_ID = YEAR_TWO.ACCOUNT_ID
WHERE TABLE_NAME.YEAR = 2019
AND TABLE_NAME.QUANTITY = 0
GROUP BY TABLE_NAME.YEAR
I'm currently working on a project in which I want to aggregate data (resolution = 15 minutes) to weekly values.
I have 4 weeks and the view should include a value for each week AND every station.
My dataset includes more than 50 station.
What I have is this:
select name, avg(parameter1), avg(parameter2)
from data
where week in ('29','30','31','32')
group by name
order by name
But it only displays the avg value of all weeks. What I need is avg values for each week and each station.
Thanks for your help!
The problem is that when you do a 'GROUP BY' on just name you then flatten the weeks and you can only perform aggregate functions on them.
Your best option is to do a GROUP BY on both name and week so something like:
select name, week, avg(parameter1), avg(parameter2)
from data
where week in ('29','30','31','32')
group by name, week
order by name
PS - It' not entirely clear whether you're suggesting that you need one set of results for stations and one for weeks, or whether you need a set of results for every week at every station (which this answer provides the solution for). If you require the former then separate queries are the way to go.
I have an SQLite database with the following fields for example:
date (yyyymmdd fomrat)
total (0.00 format)
There is typically 2 months of records in the database. Does anyone know a SQL query to find a weekly average?
I could easily just execute:
SELECT COUNT(1) as total_records, SUM(total) as total FROM stats_adsense
Then just divide total by 7 but unless there is exactly x days that are divisible by 7 in the db I don't think it will be very accurate, especially if there is less than 7 days of records.
To get a daily summary it's obviously just total / total_records.
Can anyone help me out with this?
You could try something like this:
SELECT strftime('%W', thedate) theweek, avg(total) theaverage
FROM table GROUP BY strftime('%W', thedate)
I'm not sure how the syntax would work in SQLite, but one way would be to parse out the date parts of each [date] field, and then specifying which WEEK and DAY boundaries in your WHERE clause and then GROUP by the week. This will give you a true average regardless of whether there are rows or not.
Something like this (using T-SQL):
SELECT DATEPART(w, theDate), Avg(theAmount) as Average
FROM Table
GROUP BY DATEPART(w, theDate)
This will return a row for every week. You could filter it in your WHERE clause to restrict it to a given date range.
Hope this helps.
Your weekly average is
daily * 7
Obviously this doesn't take in to account specific weeks, but you can get that by narrowing the result set in a date range.
You'll have to omit those records in the addition which don't belong to a full week. So, prior to summing up, you'll have to find the min and max of the dates, manipulate them such that they form "whole" weeks, and then run your original query with a WHERE that limits the date values according to the new range. Maybe you can even put all this into one query. I'll leave that up to you. ;-)
Those values which are "truncated" are not used then, obviously. If there's not enough values for a week at all, there's no result at all. But there's no solution to that, apparently.
I have 2 tables from which i need to run a query to display number of views a user had in the last 3 months from now.
So far I have come up with: all the field types are correct.
SELECT dbo_LU_USER.USERNAME
, Count(*) AS No_of_Sessions
FROM dbo_SDB_SESSION
INNER JOIN dbo_LU_USER
ON dbo_SDB_SESSION.FK_USERID = dbo_LU_USER.PK_USERID
WHERE (((DateDiff("m",[dbo_SDB_SESSION].[SESSIONSTART],Now()))=0
Or (DateDiff("m",[dbo_SDB_SESSION].[SESSIONSTART],Now()))=1
Or (DateDiff("m",[dbo_SDB_SESSION].[SESSIONSTART],Now()))=2))
GROUP BY dbo_LU_USER.USERNAME;
Basically, the code above display a list of all records within the past 3 months; however, it starts from the 1st day of the month and ends on the current date, but I need it to start 3 months prior to today's date.
Also to let you know this is SQL View in MS Access 2007 code.
Thanks in advance
Depending on how "strictly" you define your 3 months rule, you could make things a lot easier and probably efficient, by trying this:
SELECT dbo_LU_USER.USERNAME, Count(*) AS No_of_Sessions
FROM dbo_SDB_SESSION
INNER JOIN dbo_LU_USER
ON dbo_SDB_SESSION.FK_USERID = dbo_LU_USER.PK_USERID
WHERE [dbo_SDB_SESSION].[SESSIONSTART] between now() and DateAdd("d",-90,now())
GROUP BY dbo_LU_USER.USERNAME;
(Please understand that my MS SQL is a bit rusty, and can't test this at the moment: the idea is to make the query scan all record whose date is between "TODAY" and "TODAY-90 days").