SQL Server 2008, rendered in html via aspx webpage.
What I want to achieve, is to get an average per day figure that makes allowance for missing days. To do this I need to count the number of active days in a table.
Example:
Date | Amount
---------------------
2014-08-16 | 234.56
2014-08-16 | 258.30
2014-08-18 | 25.84
2014-08-19 | 259.21
The sum of the lot (777.961) divided by the number of active days (3) would = 259.30
So it needs to go "count number of different dates in the returned range"
Is there a tidy way to do this?
If you just want that one row of output then this should work:
select sum(amount) / count(distinct date) as your_average
from your_table
Fiddle:
http://sqlfiddle.com/#!2/7ffd1/1/0
I don't know this will be help to you, how about using Group By, Avg, count function.
SELECT Date, AVG(Amount) AS 'AmountAverage', COUNT(*) AS 'NumberOfActiveDays'
FROM YourTable WITH(NOLOCK)
GROUP BY Date
About AVG function, see here: Link
Related
I am using postgres and, I recently encountered that the code I am using has too many roundtrips.
What I am doing is basically getting data from a table on a daily basis because I have to look for changes on a daily basis, but the whole function that does this job is called once a month.
An example of my table
Amount
Id | Itemid | Amount | Date
1 | 2 | 50 | 20-5-20
Now this table can be updated to add items at any point in time and I have to see the total amount that is SUM(Amount) every day.
But here's the catch, I have to add interest to the amount of each day at the rate of 5%.
So I can't just once call the function, I have to look at its value every day.
For example if I add an item of 50$ on the 1st of may then the interest on that day is 5/100*50
I add another item on the 5th of may worth 50$ and now the interest on the 5th day is 5/100*50.
But prior to 5th, the interest was on only 50$ so If I just simply use SUM(Amount)*5/100. It is wrong.
Also, another issue is the fact that dates are stored as timestamps and I need to group it by date of the timestamp because if I group it on the basis of timestamp then it will create multiple rows for the same date which I want to avoid while taking the sum.
So if there are two entries on the same date but different hours ideally the query should sum it up as one single date.
Example
Amount Table
Date | Amount
2020-5-5 20:8:8 100
2020-5-5 7:8:8 | 100
Result should be
Amount Table
Date | Amount
2020-5-5 200
My current code.
for i in numberofdaysinthemonth:
amount = amount + session.query(func.sum(Amount.Amount)).filter(Amount.date<current_date).scalar() * 5/100
I want a query that gets all these values according to dates, for example
date | Sum of amount till that date
20-5-20 | 50
20-6-20 | 100
Any ideas about what I should do to avoid a loop that runs 30 times since the function is called once in a month.
I am supposed to get all this data in a table daywise and aggregated as the sum of amount for each day
That is a simple "running total"
select "date",
sum(amount) over (order by "date") as amount_til_date
from the_table
order by "date";
If you need the amount per itemid
select "date",
sum(amount) over (partition by itemid order by "date") as amount_til_date
from the_table
order by "date";
If you also need to calculate the "compound interest rate" up to that day, you can do that as well:
select item_id,
"date",
sum(amount) over (partition by itemid order by "date") as amount_til_date,
sum(amount) over (partition by item_id order by "date") * power(1.05, count(*) over (partition by item_id order by "date")) as compound_interest
from the_table
order by "date";
To get that for a specific month, add a WHERE clause:
where "date" >= date '2020-06-01'
and "date" < date '2020-07-01'
In general to avoid round trips between application and database, application code must be moved from application to database in stored code (stored procedures an stored functions) using a procedural language. This approach is sometimes called "thick database" in commercial databases like Oracle Database.
PostgreSQL default procedural language is pl/pgsql but you can use Java, Perl, Python, Javascript using PostgreSQL extensions that you would need to install in PostgreSQL.
I'm trying to create a "Percentage of Total" column and currently using a subquery with no issues:
SELECT ID, COUNT(*), COUNT(*) / (SELECT COUNT(*)
FROM DATA) AS % OF TOTAL FROM DATA GROUP BY ID;
| ID | COUNT | % OF TOTAL |
| 1 | 100 | 0.10 |
| 2 | 800 | 0.80 |
| 3 | 100 | 0.10 |
However, for reasons outside the scope of this question, I'm looking to see if there is any way to accomplish this without using a subquery. Essentially, the application uses logic outside of the SQL query to determine what the WHERE clause is and injects it into the query. That logic does not account for the existence of subqueries like the above, so before going back and rebuilding all of the existing logic to account for this scenario, I figured I'd see if there's another solution first.
I've tried accomplishing this effect with a window function, but to no avail.
Use window functions:
SELECT ID, COUNT(*),
COUNT(*) / SUM(COUNT(*)) OVER () AS "% OF TOTAL"
FROM DATA
GROUP BY ID;
SELECT id, count(*) AS ct
, round(count(*)::numeric
/ sum(count(*)) OVER (ORDER BY id), 2) AS pct_of_running_total
FROM data
GROUP BY id;
You must add ORDER BY to the window function or the order of rows is arbitrary. I may seem correct at first, but that can change any time and without warning. It seems you want to order rows by id.
And you obviously don't want integer division, which would truncate fractional digits. I cast to numeric and round the result to two fractional digits like in your result.
Related answer:
Postgres window function and group by exception
Key to understanding why this works is the sequence of evens in a SELECT query:
Best way to get result count before LIMIT was applied
I am working on an old web app that is still using MS Access as it's data source and I have ran into issue while trying to rank SUM() values.
Let's say I have 2 different account numbers each of those account numbers has an unknown number of invoices. I need to sum up the total of all the invoices, group it by account number then add a rank (1-2).
RAW TABLE EXAMPLE...
Account | Sales | Invoice Number
001 | 400 | 123
002 | 150 | 456
001 | 300 | 789
DESIRED RESULTS...
Account | Sales | Rank
001 | 700 | 1
002 | 150 | 2
I tried...
SELECT Account, SUM(Sales) AS Sales,
(SELECT COUNT(*) FROM Invoices) AS RANK
FROM Invoices
ORDER BY Account
But that query keeps returning the number of records assigned to that account and not a rank.
This would be easier in a report, with a running count: Report - Running Count within a Group
This is not standard in a query, but you can do something with custom functions (it's elaborate, but possible):
http://support.microsoft.com/kb/94397/en-us
Easiest way is to break it up in to 2 queries, the first one is this and I've saved it as qryInvoices:
SELECT Invoices.Account, Sum(Invoices.Sales) AS Sales
FROM Invoices
GROUP BY Invoices.Account;
And then the second query uses the first as follows:
SELECT qryInvoices.Account, qryInvoices.Sales, (SELECT Count(*) FROM qryInvoices AS I WHERE I.Sales > qryInvoices.Sales)+1 AS Rank
FROM qryInvoices
ORDER BY qryInvoices.Sales DESC;
I've tested this and got the desired results as outlined in the question.
Note: It may be possible to achieve in one query using a Defined table, but in this instance it was looking a little ugly.
If you need the answer in one query, it should be
SELECT inv.*, (
SELECT 1+COUNT(*) FROM (
SELECT Account, Sum(Sales) AS Sum_sales FROM Invoices GROUP BY Account
) WHERE Sum_sales > inv.Sum_sales
) AS Rank
FROM (
SELECT Account, Sum(Sales) AS Sum_sales FROM Invoices GROUP BY Account
) inv
I have tried it on Access and it works. You may also use different names for the two instances of "Sum_sales" above to avoid confusion (in which case you can drop the "inv." prefix).
What is the most efficient way to get a list of all of the unique Mondays from a date field?
When I'm not all that concerned about efficiency, I have done something like:
DATE-weekday(DATE) + 1. But now I need to compute this on a large dataset and I don't want my user wishing for a Rubik's cube because it is taking so long. :)
Yes, the field is indexed.
EDIT:
What I need is a list of all of the weeks that contain records. I am creating a payroll report where the user will select the week to filter the report.
Here is what I came up with:
SELECT DISTINCT ((DATE(`timStart`)-DAYOFWEEK(`timStart`))+2)
FROM `time`
ORDER BY 1 DESC
Anyone have any improvement to suggest?
"unique mondays from a date field" should be as simple as:
SELECT DISTINCT(`date`) FROM `table` WHERE WEEKDAY(`date`)=0
"weeks in which we have date values" should be as simple as:
SELECT DISTINCT(WEEK(`date`)) FROM `table` WHERE YEAR(`date`)=2010;
SELECT WEEK(now()),YEAR(now());
+-------------+-------------+
| WEEK(now()) | YEAR(now()) |
+-------------+-------------+
| 31 | 2010 |
+-------------+-------------+
which will benefit you as well in your other payroll queries, using
WHERE WEEK(`date`)=31
Put your trust in mysql to handle things from there.
Please help me to write the following sql. I have a table like this, with an amount column and date column
amount date
-----------------------
100 - 2010-02-05
200 - 2010-02-05
50 - 2010-02-06
10 - 2010-02-06
10 2010-02-07
what I want is to write a sql to get total for each day. Ultimately my query should return something like this
amount date
-----------------
300 - 2010-02-05
60 - 2010-02-06
10 - 2010-02-07
Please note that now it has group by dates and amounts are summed for that date.
RESOLVED -
This was my bad, even though I mention the date column as date here, my actual date column in postgres table was 'timestamp'. Once I changed it to get the date only, everything got working
my working sql is like this "select sum(amount), date(date)
from bills
group by date(date)
"
thanks everyone (and I will accept the 1st answer as the correct answer since I can accept only one answer)
thanks again
sameera
Pretty basic group by statement.
SELECT SUM(table.amount), table.date
FROM table
GROUP BY table.date
http://www.w3schools.com/sql/sql_groupby.asp
Look into GROUPING by date, here: http://www.w3schools.com/sql/sql_groupby.asp
and look into SUM(), here: http://www.w3schools.com/sql/sql_func_sum.asp
You will need to use both of them.
Try this:
SELECT SUM(Amount), Date FROM Table
GROUP BY Date
SELECT SUM(amount) as amount_sum, date FROM table GROUP BY date;