So I've been just re-familiarizing myself with SQL after some time away from it, and I am using Mode Analytics sample Data warehouse, where they have a dataset for SF police calls in 2014.
For reference, it's set up as this:
incident_num, category, descript, day_of_week, date, time, pd_district, Resolution, address, ID
What I am trying to do is figure out the total number of incidents for a category, and a new column of all the people who have been arrested. Ideally looking something like this
Category, Total_Incidents, Arrested
-------------------------------------
Battery 10 4
Murder 200 5
Something like that..
So far I've been trying this out:
SELECT category, COUNT (Resolution) AS Total_Incidents, (
Select COUNT (resolution)
from tutorial.sf_crime_incidents_2014_01
where Resolution like '%ARREST%') AS Arrested
from tutorial.sf_crime_incidents_2014_01
group by 1
order by 2 desc
That returns the total amount of incidents correctly, but for the Arrested, it keeps printing out 9014 Arrest
Any idea what I am doing wrong?
The subquery is not correlated. It just selects the count of all rows. Add a condition, that checks for the category to be equal to that of the outer query.
SELECT o.category,
count(o.resolution) total_incidents,
(SELECT count(i.resolution)
FROM tutorial.sf_crime_incidents_2014_01 i
WHERE i.resolution LIKE '%ARREST%'
AND i.category = o.category) arrested
FROM tutorial.sf_crime_incidents_2014_01 o
GROUP BY 1
You could use this:
SELECT category,
COUNT(Resolution) AS Total_Incidents,
SUM(CASE WHEN Resolution LIKE '%ARREST%' THEN 1 END) AS Arrested
FROM tutorial.sf_crime_incidents_2014_01
GROUP BY category
ORDER BY 2 DESC;
Related
I am working on some car accident data and am stuck on how to get the data in the form I want.
select
sex_of_driver,
accident_severity,
count(accident_severity) over (partition by sex_of_driver, accident_severity)
from
SQL.dbo.accident as accident
inner join SQL.dbo.vehicle as vehicle on
accident.accident_index = vehicle.accident_index
This is my code, which counts the accidents had per each sex for each severity. I know I can do this with group by but I wanted to use a partition by in order to work out % too.
However I get a very large table (I assume for each row that is each sex/severity. When I do the following:
select
sex_of_driver,
accident_severity,
count(accident_severity) over (partition by sex_of_driver, accident_severity)
from
SQL.dbo.accident as accident
inner join SQL.dbo.vehicle as vehicle on
accident.accident_index = vehicle.accident_index
group by
sex_of_driver,
accident_severity
I get this:
sex_of_driver
accident_severity
(No column name)
1
1
1
1
2
1
-1
2
1
-1
1
1
1
3
1
I won't give you the whole table, but basically, the group by has caused the count to just be 1.
I can't figure out why group by isn't working. Is this an MS SQL-Server thing?
I want to get the same result as below (obv without the CASE etc)
select
accident.accident_severity,
count(accident.accident_severity) as num_accidents,
vehicle.sex_of_driver,
CASE vehicle.sex_of_driver WHEN '1' THEN 'Male' WHEN '2' THEN 'Female' end as sex_col,
CASE accident.accident_severity WHEN '1' THEN 'Fatal' WHEN '2' THEN 'Serious' WHEN '3' THEN 'Slight' end as serious_col
from
SQL.dbo.accident as accident
inner join SQL.dbo.vehicle as vehicle on
accident.accident_index = vehicle.accident_index
where
sex_of_driver != 3
and
sex_of_driver != -1
group by
accident.accident_severity,
vehicle.sex_of_driver
order by
accident.accident_severity
You seem to have a misunderstanding here.
GROUP BY will reduce your rows to a single row per grouping (ie per pair of sex_of_driver, accident_severity values. Any normal aggregates you use with this, such as COUNT(*), will return the aggregate value within that group.
Whereas OVER gives you a windowed aggregated, and means you are calculating it after reducing your rows. Therefore when you write count(accident_severity) over (partition by sex_of_driver, accident_severity) the aggregate only receives a single row in each partition, because the rows have already been reduced.
You say "I know I can do this with group by but I wanted to use a partition by in order to work out % too." but you are misunderstanding how to do that. You don't need PARTITION BY to work out percentage. All you need to calculate a percentage over the whole resultset is COUNT(*) * 1.0 / SUM(COUNT(*)) OVER (), in other words a windowed aggregate over a normal aggregate.
Note also that count(accident_severity) does not give you the number of distinct accident_severity values, it gives you the number of non-null values, which is probably not what you intend. You also have a very strange join predicate, you probably want something like a.vehicle_id = v.vehicle_id
So you want something like this:
select
sex_of_driver,
accident_severity,
count(*) as Count,
count(*) * 1.0 /
sum(count(*)) over (partition by sex_of_driver) as PercentOfSex
count(*) * 1.0 /
sum(count(*)) over () as PercentOfTotal
from
dbo.accident as accident a
inner join dbo.vehicle as v on
a.vehicle_id = v.vehicle_id
group by
sex_of_driver,
accident_severity;
I am pretty much stuck with a problem I am facing with SQL Server. I want to show in a query the amount of times that specific value occurs. This is pretty easy to do, but I want to take it a step further and I think the best way to explain on what I am trying to achieve is to explain it using images.
I have two tables:
Plant and
Chest
As you can see with the chest the column 'hoeveelheid' tells how full the chest is, 'vol' == 1 and 3/4 is == 0,75. In the plant table there is a column 'Hoeveelheidperkist' which tells how much plants there can be in 1 chest.
select DISTINCT kist.Plantnaam, kist.Plantmaat, count(*) AS 'Amount'
from kist
group by kist.plantnaam, kist.Plantmaat
This query counts all the chests, but it does not seperate the count of 'Vol' chests and '3/4' chests. It only does This. What I want to achieve is this. But I have no idea how. Any help would be much appreciated.
If you use group by you don't need distinct
and if you want the seprated count for hoeveelheid you ust add to the group by clause
select DISTINCT kist.Plantnaam, kist.Plantmaat, kist.hoeveelheid, count(*) AS 'Amount'
from kist
group by kist.plantnaam, kist.Plantmaat, hoeveelheid
or if you want all the 3 count ond the samw rowx you could use a condition aggreagtion eg:
select DISTINCT kist.Plantnaam, kist.Plantmaat
, sum(case when kist.hoeveelheid ='Vol' then 1 else 0 end) vol
, sum(case when kist.hoeveelheid ='3/3' then 1 else 0 end) 3_4
, count(*) AS 'Amount'
from kist
group by kist.plantnaam, kist.Plantmaat
When you want to filter the data on the counts you have to use having clause. When ever you are using aggregate functions(sum, count, min, max) and you want to filter them on aggregation basis, use having clause
select DISTINCT kist.Plantnaam, kist.Plantmaat, count(*) AS 'Amount'
from kist
group by kist.plantnaam, kist.Plantmaat having count(*) = 1 -- or provide necessary conditions
I want to write a query that allows me to only get the specific data I want and nothing more.
We will use TV's as an example. I have three brands of TVs and I want to see the top ten selling models of each brand. I only want to return 30 rows. One solution is unions, but that can get messy fast. Ideally there would be a WHERE ROWNUM grouping by situation.
SELECT
A.Brand
, A.Model
, A.Sales
FROM
( SELECT
TV.Brand
, TV.Model
, SUM(TV.SALES) AS SALES
FROM TV_TABLE as TV
ORDER BY
TV.Brand
, SALES DESC
) A
WHERE ROWNUM <10
In my code above I will get the top 10 total results from the inner query, but not 10 from each Grouping.
What I want to see is something like this:
Brand: Model: Sales
Sony: x10: 20
Sony: X20: 18
Sony: X30: 10
VISIO: A40: 40
VISIO: A20: 10
This is an oversimplified example, in practice I'll need to have 20-50 gropings and would like to avoid downloading all of the data and using a Pivot feature.
select Brand, Model, SALES
from(
select Brand, Model, SALES,row_number()over(partition by Brand order by SALES desc) rn
from (
SELECT TV.Brand, TV.Model,SUM(TV.SALES) AS SALES,
FROM TV_TABLE as TV
group BY TV.Brand,TV.Model
)a
)b
where rn <= 10
SELECT TV.Brand, TV.Model, SUM(TV.SALES) AS SALES
FROM TV_TABLE TV
group by TV.Brand, TV.Model
order by SUM(TV.SALES) desc, TV.Brand
limit 30
I'm trying to add the counts together and output the one with the max counts.
The question is: Display the person with the most medals (gold as place = 1, silver as place = 2, bronze as place = 3)
Add all the medals together and display the person with the most medals
Below is the code I have thought about (obviously doesn't work)
Any ideas?
Select cm.Givenname, cm.Familyname, count(*)
FROM Competitors cm JOIN Results re ON cm.competitornum = re.competitornum
WHERE re.place between '1' and '3'
group by cm.Givenname, cm.Familyname
having max (count(re.place = 1) + count(re.place = 2) + count(re.place = 3))
Sorry forgot to add that were not allowed to use ORDER BY.
Some data in the table
Competitors Table
Competitornum GivenName Familyname gender Dateofbirth Countrycode
219153 Imri Daniel Male 1988-02-02 Aus
Results Table
Eventid Competitornum Place Lane Elapsedtime
SWM111 219153 1 2 20 02
From what you've described it sounds like you just need to take the "Top" individual in the total medal count. In order to do that you would write something like this.
Select top 1 cm.Givenname, cm.Familyname, count(*)
FROM Competitors cm JOIN Results re ON cm.competitornum = re.competitornum
WHERE re.place between '1' and '3'
group by cm.Givenname, cm.Familyname
order by count(*) desc
Without using order by you have a couple of other options though I'm glossing over whatever syntax peculiarities sqlfire may use.
You could determine the max medal count of any user and then only select competitors that have that count. You could do this by saving it out to a variable or using a subquery.
Select cm.Givenname, cm.Familyname, count(*)
FROM Competitors cm JOIN Results re ON cm.competitornum = re.competitornum
WHERE re.place between '1' and '3'
group by cm.Givenname, cm.Familyname
having count(*) = (
Select max( count(*) )
FROM Competitors cm JOIN Results re ON cm.competitornum = re.competitornum
WHERE re.place between '1' and '3'
group by cm.Givenname, cm.Familyname
)
Just a note here. This second method is highly inefficient because we recalculate the max medal count for every row in the parent table. If sqlfire supports it you would be much better served by calculating this ahead of time, storing it in a variable and using that in the HAVING clause.
You are grouping by re.place, is that what you want? You want the results per ... ? :)
[edit] Good, now that's fixed you're almost there :)
The having is not needed in this case, you simply need to add a count(re.EventID) to your select and make a subquery out of it with a max(that_count_column).
Imagine I have a table showing the sales of Acme Widgets, and where they were sold. It's fairly easy to produce a report grouping sales by country. It's fairly easy to find the top 10. But what I'd like is to show the top 10, and then have a final row saying Other. E.g.,
Ctry | Sales
=============
GB | 100
US | 80
ES | 60
...
IT | 10
Other | 50
I've been searching for ages but can't seem to find any help which takes me beyond the standard top 10.
TIA
I tried some of the other solutions here, however they seem to be either slightly off, or the ordering wasn't quite right.
My attempt at a Microsoft SQL Server solution appears to work correctly:
SELECT Ctry, Sales FROM
(
SELECT TOP 2
Ctry,
SUM(Sales) AS Sales
FROM
Table1
GROUP BY
Ctry
ORDER BY
Sales DESC
) AS Q1
UNION ALL
SELECT
Ctry AS 'Other',
SUM(Sales) AS Sales
FROM
Table1
WHERE
Ctry NOT IN (SELECT TOP 2
Ctry
FROM
Table1
GROUP BY
Ctry
ORDER BY
SUM(Sales) DESC)
Note that in my example, I'm only using TOP 2 rather than TOP 10. This is simply due to my test data being rather more limited. You can easily substitute the 2 for a 10 in your own data.
Here's the SQL Script to create the table:
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
SET ANSI_PADDING ON
GO
CREATE TABLE [dbo].[Table1](
[Ctry] [varchar](50) NOT NULL,
[Sales] [float] NOT NULL
) ON [PRIMARY]
GO
SET ANSI_PADDING OFF
And my data looks like this:
GB 10
GB 21.2
GB 34
GB 16.75
US 10
US 11
US 56.43
FR 18.54
FR 98.58
WE 44.33
WE 11.54
WE 89.21
KR 10
PO 10
DE 10
Note that the query result is correctly ordered by the Sales value aggregate and not the alphabetic country code, and that the "Other" category is always last, even if it's Sales value aggregate would ordinarily push it to the top of the list.
I'm not saying this is the best (read: most optimal) solution, however, for the dataset that I provided it seems to work pretty well.
SELECT Ctry, sum(Sales) Sales
FROM (SELECT COALESCE(T2.Ctry, 'OTHER') Ctry, T1.Sales
FROM (SELECT Ctry, sum(Sales) Sales
FROM Table1
GROUP BY Ctry) T1
LEFT JOIN
(SELECT TOP 10 Ctry, sum(sales) Sales
FROM Table1
GROUP BY Ctry) T2
on T1.Ctry = T2.Ctry
) T
GROUP BY Ctry
The pure SQL solutions to this problem make multiple passes through the individual records more than once. The following solution only queries the data once, and uses a SQL ranking function, ROW_NUMBER() to determine if some results belong in the "Other" category. The ROW_NUMBER() function has been available in SQL Server since SQL Server 2008. In my database, this seems to have resulted in a more efficient query. Please note that the "Other" row will appear above some rows if the total of the "Other" sales exceeds the top 10. If this is not desired some adjustments would need to be made to this query:
SELECT CASE WHEN RowNumber > 10 THEN 'Other' ELSE Ctry END AS Ctry,
SUM(Sales) as Sales FROM
(
SELECT Ctry, SUM(Sales) as Sales,
ROW_NUMBER() OVER(ORDER BY SUM(Sales) DESC) AS RowNumber
FROM Table1 GROUP BY Ctry
) as AggregateQuery
GROUP BY CASE WHEN RowNumber > 10 THEN 'Other' ELSE Ctry END
ORDER BY SUM(Sales) DESC
Using a real analytics SQL engine, such as Apache Spark, you can use Common Table Expression with to do:
with t as (
select rank() over (order by sales desc) as r, sales,city
from DB
order by sales desc
)
select sales, city, r
from t where r <= 10
union
select sum(sales) as sales, "Other" as city, 11 as r
from t where r > 10
In pseudo SQL:
select top 10 order by sales
UNION
select 'Other',SUM(sales) where Ctry not in (select top 10 like above)
Union the top ten with an outer Join of the top ten with the table it self to aggregate the rest.
I don't have access to SQL here but I'll hazzard a guess:
select top (10) Ctry, sales from table1
union all
select 'other', sum(sales)
from table1
left outer join (select top (10) Ctry, sales from table1) as table2
on table2.Ctry = table2.Ctry
where table2.ctry = null
group by table1.Ctry
Of course if this is a rapidly changing top(10) then you either lock or maintain a copy of the top(10) for the duration of the query.
Have in mind that depending on your use (and database volume / restrictions) you can achieve the same results using application code (python, node, C#, java etc). Sure it will depend on your use-case but hey, it's possible.
I ended up doing this in C# for instance:
// Mockup Class that has a CATEGORY and it's VOLUME
class YourModel { string category; double volume; }
List<YourModel> groupedList = wholeList.Take (5).ToList ();
groupedList.Add (new YourModel()
{
category = "Others",
volume = tempChartData.Skip (5).Select (t => t.qtd).Sum ()
});
Disclaimer
I understand that this is a "SQL Only" tagged question, but there might be other people like me out there who can make use of the application layer instead of relying only on SQL to make it happen. I am just trying to show people other ways of doing the same thing, that might be helpful. Even if this gets downvoted to oblivion I know that someone will be happy to read this because they were taught to use each tool to it's best, and think "outside the box".