I am trying to find a division with the lowest population density to do so i did the following:
SELECT P.edname, MIN((P.total_area*1000)/P.total2011) AS "Lowest population density"
FROM eds_census2011 P
GROUP BY P.edname
HAVING COUNT (*)> 1
total_area is multiplied by 1000 (so it is in square metres) and divide by total population.
I want only one record displaying the division (edname) and the population density wich is calculated (MIN((P.total_area*1000)/P.total2011)), instead I get all the records - not even sorted...
The problem is that I have to group it by edname, if I leave out the GROUP BY and HAVING lines I get an error. Any help is greatly appriciated!
Try
SELECT edname, (total_area*1000/total2011) density
FROM eds_census2011
WHERE (total_area*1000/total2011) = (SELECT MIN(total_area*1000/total2011) FROM eds_census2011)
SQLFiddle
A 'Return only one row' rule could be easily enforced by using LIMIT 1 if it's really necessary
Without subquery:
SELECT p.edname, min((p.total_area * 1000)/p.total2011) AS lowest_pop
FROM eds_census2011 p
GROUP BY p.edname
HAVING COUNT (*) > 1
ORDER BY 2
LIMIT 1;
This one returns only 1 row (if any qualify), even if multiple rows have equally low density.
If you just want the lowest density, period, this can be much simpler:
SELECT edname, (total_area * 1000)/total2011) AS lowest_pop
FROM eds_census2011
ORDER BY 2
LIMIT 1;
Related
I am trying to get a total hours from a dataset and because you can have the same asset with the same company (company_B) twice at two different times I have this join issue. I know I want the min for company_B gone and the Max for company_B gone because they represent wrong dates being matched. The negative is easy but what about the Max?
I have:
AssetID------StartDate-------FinishDate-------CompanyName----HoursOnSite
22222-------2016-02-12-------2016-02-20-------Company_A--------192
22222-------2016-02-01-------2016-02-09-------Company_B--------208 (keep)
22222-------2016-02-12-------2016-02-09-------Company_B-------(-56) (remove)
22222-------2016-02-01-------2016-02-21-------Company_B--------480 (remove)
22222-------2016-02-12-------2016-02-21-------Company_B--------216 (keep)
55555-------2016-02-18-------2016-02-22-------Company_C--------96
99584-------2016-02-22-------2016-02-25-------Company_D--------63
I think you can do the query for the records with max and min HoursOnSite for company B, and use (not in) or not equal to exclude those records.
If you still have concern, please paste your query.
I'm assuming that there has to be atleast 3 instances of unique assetid - companyname combination for the Max, Min filters to work. You can change it in the final where statement tO suit your requirement
WITH CTE
AS (
SELECT *
,count(CompanyName) OVER (PARTITION BY AssetID,CompanyName) AS a
FROM <TABLE_NAME>
)
SELECT *
FROM CTE
WHERE HoursOnSite NOT IN (
SELECT MAX(HoursOnSite)
FROM <TABLE_NAME>
)
AND gdp NOT IN (
SELECT min(HoursOnSite)
FROM <TABLE_NAME>
)
AND a > 2 --MODIFY AS PER YOUR REQUIREMENT
I'm working on some SQL code as part of my University work. The data is factitious just to be clear. I'm trying to count the occurances of 1 & 0 in the SQL table Fact_Stream, this is stored in the Free_Stream column/attribute as a Boolean/bit value.
As calculations cant be made on bit values (at least in the way I'm trying) I've converted the value to an integer -- Just to be clear on that. The table contains information on a streaming companies streams, a 1 indicates the stream was free of charge, a 0 indicates the stream was paid for. My code:
SELECT Fact_Stream.Free_Stream, ((CAST(Free_Stream AS INT)) / COUNT(*) * 100) As 'Percentage of Streams'
FROM Fact_Stream
GROUP BY Free_Stream
The result/output is nearly where I want it to be, but it doesn't display the percentage correctly.
Output:
Using MS SQL Management Studio | MS SQL Server 2012 (I believe)
The percentage should be based on all rows, so you need to divide the count per 1/0 by a count of all rows. The easiest way to get this is utilizing a Windowed Aggregate Function:
SELECT Fact_Stream.Free_Stream,
100.0 * COUNT(*) -- count per bit
/ SUM(COUNT(*)) OVER () -- sum of those counts = count of all rows
As "Percentage of Streams"
FROM Fact_Stream
GROUP BY Free_Stream
You have INTs as a devisor and devidened(not sure I am correct with namings). So the result is also INT. Just cast one of those to decimal(notice how did I change to 100.0). Also you should debide count of elements in group to total count of rows in the table:
select Free_Stream,
(count(*) / (select count(*) from Free_Stream)) * 100.0 as 'Percentage of Streams'
from Fact_Stream
group by Free_Stream
Your equation is dividing the identifier (1 or 0) by the number of streams for each one, instead of dividing the count of free or paid by the total count. One way to do this is to get the total count first, then use it in your query:
declare #totalcount real;
select #totalcount = count(*) from Fact_Stream;
SELECT Fact_Stream.Free_Stream,
(Cast(Count(*) as real) / #totalcount)*100 AS 'Percentage of Streams'
FROM Fact_Stream
group by Fact_Stream.Free_Stream
I have a table like following :
Orderserialno SKU Units
1234-6789 2x3 5
1234-6789 4x5 7
1334-8905 4x5 2
1334-8905 6x10 2
I need to get the count of distinct orderserialno where Units are not equal within a orderserialno. There could be more combinations of Sku's in an order than what I have mentioned but the eventual goal is to get those orders where units corresponding to various SKUs (in that order) are not equal.
In the above case I should get answer as 1 as orderserialno 1234-6789 has different units.
Thanks
This is a relatively simple GROUP BY query:
SELECT Orderserialno, Units
FROM MyTable
GROUP BY Orderserialno, Units
HAVING COUNT(1) > 1
This would give you all pairs (Orderserialno, Units). To project out the Units, nest this query inside a DISTINCT, like this:
SELECT DICTINCT(Orderserialno) FROM (
SELECT Orderserialno, Units
FROM MyTable
GROUP BY Orderserialno, Units
HAVING COUNT(1) > 1
)
If you need only the total count of Orderserialnos with multiple units, replace DICTINCT(Orderserialno) with COUNT(DICTINCT Orderserialno).
To get the list of such order numbers, use an aggregation query:
select OrderSerialNo
from t
group by OrderSerialNo
having min(Units) <> max(Units)
This uses a trick to see if the units value changes. You can use count(distinct), but that usually incurs a performance overhead. Instead, just compare the minimum and maximum values. If they are different, then the value is not constant.
To get the count, use this as a subquery:
select count(*)
from (select OrderSerialNo
from t
group by OrderSerialNo
having min(Units) <> max(Units)
) t
I have a database table that Stores Maximum and Minimum Price Breaks for a Product.
Does anyone know of the SQL which say if I have a break from one Max to the Min of the next item. E.g. 1-10 12-20 I would like it to return me either the numbers that are missing or at the very least a count or bool if it can detect a break from the Absolute Min and the Absolute Max by going through each range.
SQL Server (MSSQL) 2008
For a database that supports window functions, like Oracle:
SELECT t.*
, CASE LAG(maxq+1, 1, minq) OVER (PARTITION BY prod ORDER BY minq)
WHEN minq
THEN 0
ELSE 1
END AS is_gap
FROM tbl t
;
This will produce is_gap = 1 for a row that forms a gap with the previous row (ordered by minq). If your quantity ranges can overlap, the required logic would need to be provided.
http://sqlfiddle.com/#!4/f609e/4
Something like this, giving max quantities that aren't the overall max for the product and don't have a min quantity following them:
select prev.tbProduct_Id,prev.MaxQuantity
from yourtable prev
left join (select tbProduct_ID, max(MaxQuantity) MaxQuantity from yourtable group by tbProduct_id) maxes
on maxes.tbProduct_ID=prev.tbProduct_Id and maxes.MaxQuantity=prev.MaxQuantity
left join yourtable next
on next.tbProduct_Id=prev.tbProduct_Id and next.MinQuantity=prev.MaxQuantity+1
where maxes.tbProduct_Id is null and next.tbProduct_Id is null;
This would fail on your sample data, though, because it would expect a row with MinQuantity 21, not 20.
We have this set of data that we need to get the average of a column. a select avg(x) from y does the trick. However we need a more accurate figure.
I figured that there must be a way of filtering records that has either too high or too low values(spikes) so that we can exclude them in calculating the average.
There are three types of average, and what you are originally using is the mean - the sum of all the values divided by the number of values.
You might find it more useful to get the mode - the most frequently occuring value:
select name,
(select top 1 h.run_duration
from sysjobhistory h
where h.step_id = 0
and h.job_id = j.job_id
group by h.run_duration
order by count(*) desc) run_duration
from sysjobs j
If you did want to get rid of any values outside the original standard deviation, you could find the average and the standard deviation in a subquery, eliminate those values which are outside the range : average +- standard deviation, then do a further average of the remaining values, but you start running the risk of having meaningless values:
select oh.job_id, avg(oh.run_duration) from sysjobhistory oh
inner join (select job_id, avg(h.run_duration) avgduration,
stdev(h.run_duration) stdev_duration
from sysjobhistory h
group by job_id) as m on m.job_id = oh.job_id
where oh.step_id = 0
and abs(oh.run_duration - m.avgduration) < m.stdev_duration
group by oh.job_id
in sql server there's also the STDEV function so maybe that can be of some help...