I have been stuck in complicated problem. I do not know the version of this SQL, it is school edition. But it is not relevant info now anyway.
I want order cities ascending and numbers descending. With descending numbers I mean when there is same city couple times it orders then biggest number first.
I also need row numbers, I have tried SELECT ROW_NUMBER() OVER(ORDER BY COUNT(FIRST_NAME)) row with no succes.
I have two tables called CUSTOMERS and EMPLOYEES. Both of them having FIRST_NAME, LAST_NAME, CITY.
Now I have this kind of code:
SELECT
CITY, COUNT(FIRST_NAME),
CASE WHEN COUNT(FIRST_NAME) >= 0 THEN 'CUSTOMERS'
END
FROM CUSTOMERS
GROUP BY CITY
UNION
SELECT
CITY, COUNT(FIRST_NAME),
CASE WHEN COUNT(FIRST_NAME) >= 0 THEN 'EMPLOYEES'
END
FROM EMPLOYEES
GROUP BY CITY
This SQL code gives me list like this:
CITY
NEW YORK 2 CUSTOMERS
MIAMI 1 CUSTOMERS
MIAMI 4 EMPLOYEES
LOS ANGELES 1 CUSTOMERS
CHIGACO 1 CUSTOMERS
HOUSTON 1 CUSTOMERS
DALLAS 2 CUSTOMERS
SAN JOSE 2 CUSTOMERS
SEATTLE 2 CUSTOMERS
SEATTLE 5 EMPLOYEES
BOSTON 1 CUSTOMERS
BOSTON 3 EMPLOYEES
I want it look like this:
ROW CITY
1 NEW YORK 2 CUSTOMERS
2 MIAMI 4 EMPLOYEES
3 MIAMI 1 CUSTOMERS
4 LOS ANGELES 1 CUSTOMERS
5 CHIGACO 1 CUSTOMERS
6 HOUSTON 1 CUSTOMERS
7 DALLAS 2 CUSTOMERS
8 SAN JOSE 2 CUSTOMERS
9 SEATTLE 5 EMPLOYEES
10 SEATTLE 2 CUSTOMERS
11 BOSTON 3 EMPLOYEES
12 BOSTON 1 CUSTOMERS
You can use window functions in the ORDER BY:
SELECT c.*
FROM ((SELECT CITY, COUNT(*) as cnt, 'CUSTOMERS' as WHICH
FROM CUSTOMERS
GROUP BY CITY
) UNION ALL
(SELECT CITY, COUNT(*), 'EMPLOYEES'
FROM EMPLOYEES
GROUP BY CITY
)
) c
ORDER BY MAX(cnt) OVER (PARTITION BY city) DESC,
city,
cnt DESC;
Related
I have to make a query that has the Total number of customers by country and city
country and city are columns that are inside the customer table
On my own I have managed to get the total number of customers per city like this:
SELECT city, COUNT (*)
FROM employees
GROUP BY city
ORDER BY city
But how do I get it together with the country?
looking for information I think it should be something like this and ordered from largest to smallest
Country
City
TOTAL_CUSTOMERS
USA
Kirkland
3
USA
London
2
UK
Redmond
2
UK
Seattle
1
UK
Tacoma
1
What we have been told is to say Total number of customers by country and city.
You simply add country to the column list and group by list:
SELECT country,city, COUNT(*)
FROM employees
GROUP BY country,city
ORDER BY COUNT(*) DESC
I have the following data in an orders table:
revenue expenses location_1 location_2
3 6 London New York
6 11 Paris Toronto
1 8 Houston Sydney
1 4 Chicago Los Angeles
2 5 New York London
7 11 New York Boston
4 6 Toronto Paris
5 11 Toronto New York
1 2 Los Angeles London
0 0 Mexico City London
I would like to create a result set that has 3 columns:
a list of the 10 DISTINCT city names
the sum of revenue for each city
the sum of expenses for each city
The desired result is:
location revenue expenses
London 6 13
New York 17 33
Paris 10 17
Toronto 15 28
Houston 1 8
Sydney 1 8
Chicago 1 4
Los Angeles 2 6
Boston 7 11
Mexico City 0 0
Is it possible to aggregate on distinct values across two columns? If yes, how would I do it?
Here is a fiddle:
http://sqlfiddle.com/#!9/0b1105/1
Shorter (and often faster):
SELECT location, sum(revenue) AS rev, sum(expenses) AS exp
FROM (
SELECT location_1 AS location, revenue, expenses FROM orders
UNION ALL
SELECT location_2 , revenue, expenses FROM orders
) sub
GROUP BY 1;
May be faster:
WITH cte AS (
SELECT location_1, location_2, revenue AS rev, expenses AS exp
FROM orders
)
SELECT location, sum(rev) AS rev, sum(exp) AS exp
FROM (
SELECT location_1 AS location, rev, exp FROM cte
UNION ALL
SELECT location_2 , rev, exp FROM cte
) sub
GROUP BY 1;
The (materialized!) CTE adds overhead, which may outweigh the benefit. Depends on many factors like total table size, available indexes, possible bloat, available RAM, storage speed, Postgres version, ...
fiddle
You could UNION ALL two queries and then select from it...
select location, sum(rev) as rev, sum(exp) as exp
from (
select location_1 as location, sum(revenue) as rev, sum(expenses) as exp
from orders
group by location_1
union all
select location_2 as location, sum(revenue) as rev, sum(expenses) as exp
from orders
group by location_2
)z
group by location
order by 1
I need to show the countries that have more than one individual.
Customers
customer_id first_name last_name age country
1 John Doe 31 USA
2 Robert Luna 22 USA
3 David Robinson 22 UK
4 John Reinhardt 25 UK
5 Betty Doe 28 UAE
So the query should return
customer_id first_name last_name age country
1 John Doe 31 USA
2 Robert Luna 22 USA
3 David Robinson 22 UK
4 John Reinhardt 25 UK
I tried tis query but it didn't work.
SELECT last_name, Country
FROM Customers
GROUP BY Country
HAVING COUNT(Customer_id) > 1;
The actual table can be found here
Try using the following query. Thanks
SELECT * FROM CUSTOMERS C
WHERE C.COUNTRY IN (SELECT COUNTRY FROM CUSTOMERS GROUP BY COUNTRY HAVING COUNT(*)>1)
You could use a windowed count as a filter:
with c as (
select *, Count(*) over(partition by country) cnt
from Customers
)
select *
from c
where cnt > 1;
I have 3 different tables, country, city, and customer. Tables are shown below:
country table:
id country_name
1 UK
2 US
3 Brazil
:
n Canada
city table
id city_name postal_code country_id
1 London 30090 1
2 Dallas 20909 2
3 Rio 29090 3
4 Atlanta 30318 2
:
n Vancouver 32230 n
customer table
id customer_name city_id
1 John 1
2 Pete 3
3 Dave 2
4 May 2
5 Chuck 4
6 Sam 3
7 Henry 3
***country.id is references city.country_id, and city.id is references customer.city_id
I want to write a query that can extract the country name, city name and the count of the customer of the associate city. But with one condition, the query will return all cities with more customers than the average number of customers of all cities
It will look something like below, this is the correct output
UK London 2
Brazil Rio 3
but I kept getting this output, which isn't correct
UK London 2
US Dallas 2
US Atlanta 1
Brazil Rio 3
I fixed my SQL query but it doesn't give me the result that I want
SELECT country.country_name, city.city_name, COUNT(customer.city_id) from country
JOIN city on country.id = city.country_id
JOIN customer on city.id = customer.city_id
Group by city_name,country.country_name;
I am wondering how can I do this and fix my code?
add country.country_name in group by
SELECT country.country_name, city.city_name, COUNT(customer.city_id) from country
JOIN city on country.id = city.country_id
JOIN customer on city.id = customer.city_id
Group by city_name,country.country_name
You are missing country.country_name in the query it will give you error. As a general rule all columns on which aggregate function is not applied should be part of group by clause.
So either you write your query without country_name in the select or add country_name in the group by clause.
My simple query is as follows in SQL Server Management Studio 2012:-
SELECT Last_Name, City,
(SELECT COUNT (City) FROM Customers IX WHERE IX.City = EX.City) as counting
FROM Customers EX
GROUP BY City, Last_Name
ORDER BY City
Outputs this:-
Last_Name City Counting
Joe London 3
Smith London 3
Carter London 3
Stones New York 3
Jones New York 3
White New York 3
But I would like it to not repeat the counts for the same city and output like this:-
Last_Name City Counting
Joe London 3
Smith London
Carter London
Stones New York 3
Jones New York
White New York
How would I achieve this please?
Seems like a very odd request, and easily done on the application side. But it is not that hard in SQL:
SELECT Last_Name, City,
(case when row_number() over (partition by Last_Name, City order by (select NULL)) = 1
then (SELECT COUNT(City) FROM Customers IX WHERE IX.City = EX.City) as counting
end) as Counting
FROM Customers EX
GROUP BY City, Last_Name
ORDER BY City;
This will put the value on one row for each city. It is not determinate which one, but would probably be the first in practice. You can guarantee this by using a stable sort:
SELECT Last_Name, City,
(case when row_number() over (partition by Last_Name, City order by Last_Name) = 1
then (SELECT COUNT(City) FROM Customers IX WHERE IX.City = EX.City) as counting
end) as Counting
FROM Customers EX
GROUP BY City, Last_Name
ORDER BY City, Last_Name