For my homework, I have to write sql code to show "Among all the orders in 2015, calculate the number of days for each holidaytype, and the average sales per day for each holidaytype. Exclude holidaytype=NULL. Sort the results by the average sales per day from high to low."
This is the code that I have been trying to use
select distinct holidaytype, sum(AvgSales) as AvgSales, sum(NumDays) as NumDays
from(
Select min(holidaytype) as holidaytype, count(order_date) as cnt, count(numholidays) as NumDays, avg(o.sales*o.quantity) as AvgSales
from orderline o, orders1 o1, calendar c
where o.Order_ID=o1.Order_ID and datepart(yyyy,order_date)= 2015 and holidaytype is not null) J
group by holidaytype
go
In the output, only 1 holiday type is showing but I am supposed to have 6 or 7 different holiday types.
You are grouping by Holiday Type, so it doesn't make sense to aggregate it, which isn't what you want anyway, according to your question.
So instead of this:
Select min(holidaytype) as holidaytype,
You should do this:
Select holidaytype,
Related
This is what my table looks like:
NOTE: Don't worry about the BMI field being empty in some rows. We assume that each row is a reading. I have omitted some columns for privacy reasons.
I want to get a count of the number of active customers per month. A customer is active if they have at least 18 readings in total (1 reading per day for 18 days in a given month). How do I write this SQL query? Assume the table name is 'cust'. I'm using SQL Server. Any help is appreciated.
Presumably a patient is a customer in your world. If so, you can use two levels of aggregation:
select yyyy, mm, count(*)
from (select year(createdat) as yyyy, month(createdat) as mm,
patient_id,
count(distinct convert(date, createdat)) as num_days
from t
group by year(createdat), month(createdat), patient_id
) ymp
where num_days >= 18
group by yyyy, mm;
You need to group by patient and the month, then group again by just the month
SELECT
mth,
COUNT(*) NumPatients
FROM (
SELECT
EOMONTH(c.createdat) mth
FROM cust c
GROUP BY EOMONTH(c.createdat), c.patient_id
HAVING COUNT(*) >= 18
-- for distinct days you could change it to:
-- HAVING COUNT(DISTINCT CAST(c.createdat AS date)) >= 18
) c
GROUP BY mth;
quick question for those SQL experts out there. I feel a bit stupid because I have the feeling I am close to reaching the solution but have not been able to do so.
If I have these two tables, how can I use the former one to divide a column of the second one?
WITH month_usage AS
(SELECT strftime('%m', starttime) AS month, SUM(slots) AS total
FROM Bookings
GROUP BY month)
SELECT strftime('%m', b.starttime) AS month, f.name, SUM(slots) AS usage
FROM Bookings as b
LEFT JOIN Facilities as f
ON b.facid = f.facid
GROUP BY name, month
ORDER BY month
The first one computes the total for each month
The second one is the one I want to divide the usage column by the total of each month to get the percentage
When I JOIN both tables using month as an id it messes up the content, any suggestion?
I want to divide the usage column by the total of each month to get the percentage
Just use window functions:
SELECT
strftime('%m', b.starttime) AS month,
f.name,
SUM(slots) AS usage
1.0 * SUM(slots) AS usage
/ SUM(SUM(slots)) OVER(PARTITION BY strftime('%m', b.starttime)) ratio
FROM Bookings as b
LEFT JOIN Facilities as f
ON b.facid = f.facid
GROUP BY name, month
ORDER BY month
I'm trying to get the quarter on quarter revenue growth for only the current quarter from a dataset. I currently have a query that looks something like this
Select
x.Year,
x.quarter,
x.product,
x.company_id,
y.company,
SUM(x.revenue)
FROM
company_directory y
LEFT JOIN (
SELECT
DATEPART(YEAR, #date) year,
DATEPART(QUARTER, #date) quarter,
product,
SUM(revenue)
FROM sales
WHERE year => 2018 ) x
ON y.company_id = x.company_id
The data I get is in this format
Year Quarter Product company_id company revenue
2020 Q2 Banana 1092 companyX $100
What I'm trying to do is get quarter on quarter growth for revenue if it's reporting the current quarter. So for example, in the above data, because we're in Q2-2020, I want an extra column to say QoQ is x% which will compare Q2 vs Q1 revenue. If the row is reporting Q1-2020 or Q2-2019 QoQ will be empty because neither of those are the current quarter based on today's date.
Expected result
Year Quarter Product company_id company revenue QoQ
2020 Q2 Banana 1092 companyX $100 20%
2020 Q1 Pear 1002 companyX $23 NULL
I'm not entirely sure how to go about this, haven't had much luck searching. Any idea how I can implement?
You can use window functions.
select
s.yr,
s.qt,
s.product,
s.company_id,
cd.company,
s.revenue,
1.0 * (
s.revenue
- lag(s.revenue) over(partition by s.product, s.company_id order by s.yr, s.qt)
) / lag(s.revenue) over(partition by s.product, s.company_id order by s.yr, s.qt) as QoQ
from company_directory cd
inner join (
select
datepart(year, sales_date) yr,
datepart(quarter, sales_date) qt,
product,
company_id,
sum(revenue) revenue
from sales
where sales_date >= '2018-01-01'
group by
datepart(year, sales_date) year,
datepart(quarter, sales_date) quarter,
product,
company_id
) s on s.company_id = cd.company_id
Notes:
your code is not valid MySQL; I assume that you are running SQL Server instead of MySQL
the use of a variable in the subquery does not make sense - I assume that you have a column called sales_date in table sales that holds the sales date
your group by clauses are inconsistent with your select clauses - I assume that you want the quarter to quarter sales growth per company and per product
you might need to ajust the QoQ computation to your actual definition of the quarter to quarter growth
I don't see the point for a left join, so I used inner join instead
You need analytical window function LAG
https://dbfiddle.uk/?rdbms=sqlserver_2019&fiddle=40a7ba897df766f913ebd99e2f2a0f4e
I need to find the average size (average number of employees) of all the groups (employers) that we do business with per month for the last ten years.
So I have no problem getting the average group size for each month. For the Current month I can use the following:
Select count(*)
from Employees EE
join Employers ER on EE.employerid = ER.employerid
group by ER.EmployerName
This will give me a list of how many employees are in each group. I can then copy and paste the column into excel get the average for the current month.
For the previous month, I want exclude any employees that were added after that month. I have a query for this too:
Select count(*)
from Employees EE
join Employers ER on EE.employerid = ER.employerid
where EE.dateadded <= DATEADD(month, -1,GETDATE())
group by ER.EmployerName
That will exclude all employees that were added this month. I can continue to this all the way back ten years, but I know there is a better way to do this. I have no problem running this query 120 times, copying and pasting the results into excel to compute the average. However, I'd rather learn a more efficient way to do this.
Another Question, I can't do the following, anyone know a way around it:
Select avg(count(*))
Thanks in advance guys!!
Edit: Employees that have been terminated can be found like this. NULL are employees that are currently employed.
Select count(*)
from Employees EE
join Employers ER on EE.employerid = ER.employerid
join Gen_Info gne on gne.id = EE.newuserid
where EE.dateadded <= DATEADD(month, -1,GETDATE())
and (gne.TerminationDate is NULL OR gen.TerminationDate < DATEADD(day, -14,GETDATE())
group by ER.EmployerName
Are you after a query that shows the count by year and month they were added? if so this seems pretty straight forward.
this is using mySQL date functions Year & month.
Select AVG(cnt) FROM (
Select count(*) cnt, Year(dateAdded), Month(dateAdded)
from System_Users su
join system_Employers se on se.employerid = su.employerid
group by Year(dateAdded), Month(dateAdded)) B
The inner query counts and breaks out the counts by year and month We then wrap that in a query to show the avg.
--2nd attempt but I'm Brain FriDay'd out.
This uses a Common table Expression (CTE) to generate a set of data for the count by Year, Month of the employees, and then averages out by month.
if this isn't what your after, sample data w/ expected results would help better frame the question and I can making assumptions about what you need/want.
With CTE AS (
Select Year(dateAdded) YR , Month(DateAdded) MO, count(*) over (partition by Year(dateAdded), Month(dateAdded) order by DateAdded Asc) as RunningTotal
from System_Users su
join system_Employers se on se.employerid = su.employerid
Order by YR ASC, MO ASC)
Select avg(RunningTotal), mo from cte;
I'm having an odd problem
I have a table with the columns product_id, sales and day
Not all products have sales every day. I'd like to get the average number of sales that each product had in the last 10 days where it had sales
Usually I'd get the average like this
SELECT product_id, AVG(sales)
FROM table
GROUP BY product_id
Is there a way to limit the amount of rows to be taken into consideration for each product?
I'm afraid it's not possible but I wanted to check if someone has an idea
Update to clarify:
Product may be sold on days 1,3,5,10,15,17,20.
Since I don't want to get an the average of all days but only the average of the days where the product did actually get sold doing something like
SELECT product_id, AVG(sales)
FROM table
WHERE day > '01/01/2009'
GROUP BY product_id
won't work
If you want the last 10 calendar day since products had a sale:
SELECT product_id, AVG(sales)
FROM table t
JOIN (
SELECT product_id, MAX(sales_date) as max_sales_date
FROM table
GROUP BY product_id
) t_max ON t.product_id = t_max.product_id
AND DATEDIFF(day, t.sales_date, t_max.max_sales_date) < 10
GROUP BY product_id;
The date difference is SQL server specific, you'd have to replace it with your server syntax for date difference functions.
To get the last 10 days when the product had any sale:
SELECT product_id, AVG(sales)
FROM (
SELECT product_id, sales, DENSE_RANK() OVER
(PARTITION BY product_id ORDER BY sales_date DESC) AS rn
FROM Table
) As t_rn
WHERE rn <= 10
GROUP BY product_id;
This asumes sales_date is a date, not a datetime. You'd have to extract the date part if the field is datetime.
And finaly a windowing function free version:
SELECT product_id, AVG(sales)
FROM Table t
WHERE sales_date IN (
SELECT TOP(10) sales_date
FROM Table s
WHERE t.product_id = s.product_id
ORDER BY sales_date DESC)
GROUP BY product_id;
Again, sales_date is asumed to be date, not datetime. Use other limiting syntax if TOP is not suported by your server.
Give this a whirl. The sub-query selects the last ten days of a product where there was a sale, the outer query does the aggregation.
SELECT t1.product_id, SUM(t1.sales) / COUNT(t1.*)
FROM table t1
INNER JOIN (
SELECT TOP 10 day, Product_ID
FROM table t2
WHERE (t2.product_ID=t1.Product_ID)
ORDER BY DAY DESC
)
ON (t2.day=t1.day)
GROUP BY t1.product_id
BTW: This approach uses a correlated subquery, which may not be very performant, but it should work in theory.
I'm not sure if I get it right but If you'd like to get the average of sales for last 10 days for you products you can do as follows :
SELECT Product_Id,Sum(Sales)/Count(*) FROM (SELECT ProductId,Sales FROM Table WHERE SaleDAte>=#Date) table GROUP BY Product_id HAVING Count(*)>0
OR You can use AVG Aggregate function which is easier :
SELECT Product_Id,AVG(Sales) FROM (SELECT ProductId,Sales FROM Table WHERE SaleDAte>=#Date) table GROUP BY Product_id
Updated
Now I got what you meant ,As far as I know it is not possible to do this in one query.It could be possible if we could do something like this(Northwind database):
select a.CustomerId,count(a.OrderId)
from Orders a INNER JOIN(SELECT CustomerId,OrderDate FROM Orders Order By OrderDate) AS b ON a.CustomerId=b.CustomerId GROUP BY a.CustomerId Having count(a.OrderId)<10
but you can't use order by in subqueries unless you use TOP which is not suitable for this case.But maybe you can do it as follows:
SELECT PorductId,Sales INTO #temp FROM table Order By Day
select a.ProductId,Sum(a.Sales) /Count(a.Sales)
from table a INNER JOIN #temp AS b ON a.ProductId=b.ProductId GROUP BY a.ProductId Having count(a.Sales)<=10
If this is a table of sales transactions, then there should not be any rows in there for days on which there were no Sales. I.e., If ProductId 21 had no sales on 1 June, then this table should not have any rows with productId = 21 and day = '1 June'... Therefore you should not have to filter anything out - there should not be anything to filter out
Select ProductId, Avg(Sales) AvgSales
From Table
Group By ProductId
should work fine. So if it's not, then you have not explained the problem completely or accurately.
Also, in yr question, you show Avg(Sales) in the example SQL query but then in the text you mention "average number of sales that each product ... " Do you want the average sales amount, or the average count of sales transactions? And do you want this average by Product alone (i.e., one output value reported for each product) or do you want the average per product per day ?
If you want the average per product alone, for just thpse sales in the ten days prior to now? or the ten days prior to the date of the last sale for each product?
If the latter then
Select ProductId, Avg(Sales) AvgSales
From Table T
Where day > (Select Max(Day) - 10
From Table
Where ProductId = T.ProductID)
Group By ProductId
If you want the average per product alone, for just those sales in the ten days with sales prior to the date of the last sale for each product, then
Select ProductId, Avg(Sales) AvgSales
From Table T
Where (Select Count(Distinct day) From Table
Where ProductId = T.ProductID
And Day > T.Day) <= 10
Group By ProductId