Suppose I have one table with two column, Country and City.
Country
USA
Canada
UK
City
NY
London
I want to join/merge both column records and expect the output like this -
USA
Canada
UK
NY
London
So, what will be the SQL query to merge different columns records of same table?
SELECT Country FROM TABLE
UNION
SELECT City FROM Table
should do it.
Responding to the comment "I am searching for any quick way. Because if I need to merge 10 columns then i have to write 10 Unions! Is there any other way?":
You can use an unpivot, which means you just need to add the column names into a list. Only thing is to watch for data types though. eg:
--CTE for example only
;WITH CTE_Locations as (
select Country = convert(varchar(50),'USA'), City = convert(varchar(50),'NY')
union select Country = 'Canada', City = 'Vancouver'
union select Country = 'UK', City = 'Manchester'
)
--Select a list of values from all columns
select distinct
Place
from
CTE_Locations l
unpivot (Place for PlaceType in ([Country],[City])) u
Related
Say, I have a table (named "Customers") which consists of:
CustomerName
Country
City
I am trying to list the names of all customers from cities where there are at least two customers.
This is my initial attempt:
SELECT CustomerName, City
FROM Customers
GROUP BY City
HAVING COUNT(City) > 1
This is the result that I got:
CustomerName
City
Person A
New York
Person C
Los Angeles
Here, Person A is a person from NY who appears on the top of the table and similar for Person B. However, what I wanted was the listing of all customers from New York and LA.
When I tried:
SELECT COUNT(CustomerName), City
FROM Customers
GROUP BY City
HAVING COUNT(City) > 1
I had
COUNT(CustomerName)
City
3
New York
5
Los Angeles
This means that the code is working properly, except that my original code only displays a person on top of the table from NY and LA. How do I resolve this issue?
Get cities with more than 1 customer in a subquery, and use that list to select the customers:
SELECT cst.CustomerName
FROM Customers cst
WHERE Cst.City in (
-- All cities where there are at least two customers
SELECT CstGE2.City
FROM Customers CstGE2
GROUP BY CstGE2.City
HAVING count(*) >= 2
)
How about this? I've taken the city out of the select part since you said you just wanted customer names.
SELECT a.CustomerName
FROM Customers a
WHERE (
SELECT COUNT(b.CustomerName)
FROM Customers b
WHERE b.City = a.City
) > 1
ORDER BY a.CustomerName
I am trying to select such rows that have the same specific value in one of the columns. For example, in the table below there are airlines that fly to different cities. I need to select only such airlines that fly exclusively to the usa. In the table below that would be only the airline2. The city is basically not important for the moment.
airline country_destination city_destination
airline1 usa washington
airline1 eng london
airline1 fra paris
airline2 usa new york
airline2 usa chicago
airline2 usa washington
airline3 can montreal
airline3 usa new york
airline3 can toronto
My first guess returns all the airlines, because in every of them the usa appears at least once.
select distinct airline from table1 where country_destination = 'usa'
I assume I need a nested 'select' and probably a group by airlines? Somewhere directionof what I have below? But I am stuck at this point. Any help is highly appreciated!
select airline, country_destination
from (select airline, country_destination from table1 where country_destination = 'usa' group by airline)
You do need to aggregate.
This is the simplest way I know of to do it:
select airline
from table1
group by airline
having min(country_destination) = max(country_destination)
and min(country_destination) = 'usa';
One method is to check if the airline's row count matches the conditional count (in this case, the amount of rows where the destination is 'usa').
The CTE aggregates the airline data. In the SELECT-statement you can apply the filter to only include airlines where the total row count equals the row count for destination 'usa'. If the counts between count_all and count_usa differ you know there were other country destinations.
with counts as ( select airline,
count(*) as count_all,
sum(case when country_destination == 'usa' then 1 end) as count_usa
from table1
group by 1 )
select airline
from counts
where count_all = count_usa;
you can use below with inner query-
select * from
(select distinct airline, country_destination from table1 ) t
group by airline
having count(airline) = 1 AND country_destination='usa';
I am not sure what title has to be here to correctly reflect my question, I can only describe what I want.
There is a table with fields:
id, name, city
There are next rows:
1 John London
2 Mary Paris
3 John Paris
4 Samy London
I want to get a such result:
London Paris
Total 2 2
John 1 1
Mary 0 1
Samy 1 0
So, I need to take all unique values of name and find an appropriate quantity for unique values of another field (city)
Also I want to get a total quantity of each city
Simple way to do it is:
1)Get a list of unique names
SELECT DISTINCT name FROM table
2)Get a list of unique cities
SELECT DISTINCT city FROM table
3)Create a query for every name and city
SELECT COUNT(city) FROM table WHERE name = some_name AND city = some_city
4)Get total:
SELECT COUNT(city) FROM table WHERE name = some_name
(I did't test these queries, so maybe there are some errors here but it's only to show the idea)
As there are 3 names and 2 cities -> 3 * 2 = 6 queries to DB
But for a table with 100 cities and 100 names -> 100 * 100 = 10 000 queries to DB
and it may take a lot of time to do.
Also, names and cities may be changed, so, I can't create a query with predefined names or cities as every day it's new ones, so, instead of London and Paris it may be Moscow, Turin and Berlin. The same thing with names.
How to get such table with one-two queries to original table using sqlite?
(sqlite: I do it for android)
You can get the per-name results with conditional aggregation. As for the total, unfortunately SQLite does not support the with rollup clause, that would generate it automatically.
One workaround is union all and an additional column for ordering:
select name, london, paris
from (
select name, sum(city = 'London') london, sum(city = 'Paris') paris, 1 prio
from mytable
group by name
union all
select 'Total', sum(city = 'London'), sum(city = 'Paris'), 0
from mytable
) t
order by prio, name
Actually the subquery might not be necessary:
select name, sum(city = 'London') london, sum(city = 'Paris') paris, 1 prio
from mytable
group by name
union all
select 'Total', sum(city = 'London'), sum(city = 'Paris'), 0
from mytable
order by prio, name
#GMB gave me the idea of using group by, but as I do it for SQLite on Android, so, the answer looks like:
SELECT name,
COUNT(CASE WHEN city = :london THEN 1 END) as countLondon,
COUNT(CASE WHEN city = :paris THEN 1 END) as countParis
FROM table2 GROUP BY name
where :london and :paris are passed params, and countLondon and countParis are fields of the response class
I have a string column Countries in table tblCountry for example 'India, Austrailia, US, UK'.
Now whatever sequence is supplied example 'US, Germany, UK, India, Russia' I have to split the
string on space basis and then display results of all where even a single country is present in the Column Countries value.
Upto this I had achieved by below query. Now the difficult part is I have to display the result first which
has maximum match of column value.
For example if below are the column values:
'India, Austrailia, US, Italy'
'India, Malaysia, Austrailia, US, UK'
'UK, Austrailia, France, Korea, India'
'China, India, US, UK'
and the input string is 'Austrailia, UK, India, Korea, Germany' then the result should be in maximum match comes at top like below:
Output is most matched countries on top by relevance like below for above case
'UK, Austrailia, France, Korea, India'
'India, Malaysia, Austrailia, US, UK'
'India, Austrailia, US, Italy'
'China, India, US, Brazil'
declare #matchCount int = 0;
SET #matchCount = (SELECT count(Item)
FROM dbo.SplitCountry('Austrailia, UK, India, Korea, Germany' , ',')
where Countries like '%'+Item+'%')
SELECT Countries, CASE
WHEN #matchCount >0 THEN #matchCount
ELSE 0
FROM tblCountry
I used a function to split the string 'SplitCountry'. Also I cannot use full text here
You have to
create temp table #t1 (CountriesID, Country)
create temp table #t2 (Country)
populate #t1 by using you split function, so you have:
CountriesID Country
1 India
1 Austrailia
1 US
1 Italy
2 India
2 Malaysia
2 Austrailia
2 US
2 UK
3 ... and so on
populate #t2 by using you split function so t# contains the input values
finally:
SELECT #t1.CountriesID, c.Countries
FROM #t1
INNER JOIN #t2 on #t2.Country = #t1.Country
INNER JOIN tblCountry c ON c.CountriesID = #t1.CountriesID
GROUP BY #t1.ID, c.Countries
ORDER BY COUNT(*) DESC
Finally a lot of research and I got a easy solution for my problem. Below query is perfectly working for me
DECLARE #patterns TABLE (
pattern VARCHAR(20)
);
INSERT INTO #patterns VALUES ('%india%'), ('%france%'), ('%US%'),('%UK%')
;WITH CTEORD AS
(
SELECT a.*,ROW_NUMBER() Over(Partition By country Order By p.pattern) AS RN FROM Countries a
JOIN #patterns p
ON (a.country LIKE p.pattern)
)
select MAX(RN) As RN,country,
from CTEORD group by country
order by RN desc
I want only distint city from a table but that column contains null value i dont it to come in column when i do distinct city.
select distinct city from billingsystem
the output am getting is
newyork
london
dallas
null
charles
I want output to be as
newyork
london
dallas
charles
can anybody help me out in doing this.
Use this
select distinct city from billingsystem where city is not null
The given query is correct
The Distinct keyword it use to select the distinct values only, In where condition we where mentioned like IS NOT NULL condition so from here you can get the exact answer.
select distinct city
from billingsystem
where city is not null
please try below query
select distinct city from billingsystem where city is not null