When i checked it, it doesn't remove duplication of value. Why?
example) Group by a , Group by a,b,c
Is there a difference between Group by a, Group by a,b,c ?
I wrote SQL query like this ::
SELECT COUNT(CustomerID), Country
FROM Customers
GROUP BY Country;
result ::
Table: Customers
COUNT(CustomerID) Country
---------------------------------
3 Argentina
2 Austria
2 Belgium
9 Brazil
3 Canada
2 Denmark
2 Finland
to
SELECT COUNT(CustomerID), Country
FROM Customers
GROUP BY Country, CustomerID;
Table: Customers
COUNT(CustomerID) Country
---------------------------------
1 Germany
1 Mexico
1 Mexico
1 UK
1 Sweden
1 Germany
1 France
Why doesn't tie same value changed query from Column_name?
It display all value along column_name.
I wonder if it works. thank you.
Related
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;
Can you guys let me know how to make a query that output the sum of amount based on column values(order, Continent and Country)? Also, I want to show all Continent values as unique value (North America)
Example table,
ID Code Continent Country amount
----------------------------------------------------
1 1 North America NULL NULL
2 1 America USA 10
3 1 NA USA 10
4 1 Unknown USA 10
5 2 North America NULL NULL
6 2 America Canada 15
7 2 NA Canada 15
8 2 Unknown Canada 15
9 3 North America NULL NULL
10 3 America Mexico 20
11 3 NA Mexico 20
12 3 Unknown Mexico 20
Output
ID Code Continent Country SumAmount
----------------------------------------------
1 1 North America USA 30
2 2 North America Canada 45
3 3 North America Mexico 60
I have tried to approach it like
select ID, Code, case when Continent != 'North America' then Continent = 'North America' end as Continent, Country, sum(Amount) as SumAmount
from Table group by ID, Continent, Country
or maybe I need to make a query like this and work with this query below?
select ID, Code, Continent, Country, sum(Amount) as SumAmount
from Table where Continent !='North America'
But it is not working. How should I do this?
I appreciate for any other approaches. It would be better than mine
The awkward design here (relations with no real indication of such other than the shared Code column) is going to lead to suboptimal queries like this
DECLARE #ContinentToReport varchar(32) = 'North America';
;WITH x AS
(
SELECT Code FROM dbo.TableName
WHERE Continent = #ContinentToReport
AND Country IS NULL
)
SELECT ID = ROW_NUMBER() OVER (ORDER BY x.Code),
x.Code,
Continent = #ContinentToReport,
t.Country,
SumAmount = SUM(t.amount)
FROM dbo.TableName AS t
INNER JOIN x ON t.Code = x.Code
WHERE t.Country IS NOT NULL
GROUP BY x.Code, t.Country
ORDER BY x.Code;
Output (though I made a guess at what ID means and why it's different then the ID and the source, and I find the Continent column is kind of redundant since it will always be the same):
ID
Code
Continent
Country
SumAmount
1
1
North America
USA
30
2
2
North America
Canada
45
3
3
North America
Mexico
60
Example db<>fiddle
The simplest query which returns the correct result seems to be something like this
select row_number() over (order by Code) ID,
Code,
'North America' Continent,
Country,
sum(amount) SumAmount
from dbo.TableName
where Country is not null
group by Code, Country
order by Code;
dbFiddle
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.
-----------------------
country | city | ids
-----------------------
India Mumbai 1
India Chennai 2
India Kolkata 3
---------------------
USA New York 2
USA Utah 3
---------------------
I have given a sample from a table. From the table, I am trying to query all the countries without id 1. I wrote this(Country was not included in the Where condition since it needs to apply to all the countries of the table).
Select * from Countries
WHERE id<>1
I got this.
-----------------------
country | city | ids
-----------------------
India Chennai 2
India Kolkata 3
---------------------
USA New York 2
USA Utah 3
---------------------
But I need the output to contain only USA(which does not have id=1). Is there any workaround for this?
SELECT * from Countries WHERE country not in
(SELECT country from Countries WHERE id=1)
use NOT EXISTS
Select *
from Countries c
where not exists
(
select *
from Countries x
where x.country = c.country
and x.id = 1
)
You need to group by Country like below :
SELECT C.Country
FROM City
WHERE C.Country NOT IN
(SELECT country FROM City WHERE id=1)
SQL Fiddle Demo
OR
SELECT
C.Country
FROM
City C
GROUP BY C.Country
HAVING C.Country NOT IN
(
SELECT Country FROM City WHERE Id =1
)
SQL Fiddle Demo
Let's say I have a some rows like this in a table:
SWEDEN
MEXICO
USA
SWEDEN
GERMANY
RUSSIA
MEXICO
SWEDEN
Now I need to create a script to count the countries and list them like this:
Country Amount of countries
SWEDEN 3
USA 1
MEXICO 2
RUSSIA 1
GERMANY 1
I'm stuck at:
SELECT Country
FROM dbo.Customers
How do I only show them once and create a row and count them?
Thanks a lot..
try
SELECT Country, count(*)
FROM dbo.Customers
group by Country