How would you solve this problem:
You have a table with country names and capitals like this:
tk, name, capital
How would you SELECT name where countries equals capital + "City". So you would get results like Mexico City and Panama City etc?
This question come from the following problem:
"The capital of Mexico is Mexico City. Show all the countries where the capital has the country together with the word "City".
Find the country where the capital is the country plus "City"."
You can concatenate the country's name to ' City' then compare it to its capital in the where clause:
select name
from countries
where capital = name || ' City';
Related
I made a geo game a while back where the player has to guess an item from an image (what I call an item is a SQL row basically) for example the bot sends the flag of the Netherlands, you have to type "Netherlands" to win.
Items can be the flag of a country, a capital city, a french department...
I made an info tab where it would basically give info about an item (ie region, former name, capital city, etc).
What I would like to do is properly save this information. I don't really know if I should store this in files like JSON because I would also like to give stats (Win rate per region, amount of games played per region, etc...).
Also, these elements are not fixed because some items have regions, capital cities or whatever and some don't.
Item examples :
(For a flag
Column
Attribute
ID
1
Name
United Kingdom
Former name
United Kingdom of Great Britain and Northern Ireland
Code
GB
Continent
Europe
Subregion
Northern Europe
Capital city
London
...
(For a U.S. State)
Column
Attribute
ID
1
Name
Arizona
Capital city
Phoenix
Largest city
Phoenix
...
The both solution (Add all as column and json) are not the proper way.
I think the best design is to have a key-value table.
Create Table tableName (ID INT, [Key] SYSNAME, [Value])
And data will look like:
ID
Key
Value
1
Name
Arizona
1
Capital City
Phoenix
1
Largest City
Phoenix
2
Name
United Kingdom
2
Former name
United Kingdom of Great Britain and Northern Ireland
Most valuable benefits: No Extra storage for columns with large amount of rows with NULL value.
I would appreciate a little help on some script in sql. So I have a list like the one below and a database table -Table1 with statement as a colum name, and I will like to create a column called location, where the script can search in the statement column and once it finds any of the items in the list in any row it states that in the location column
(Tema, london, Sydney, Germany, China, Africa,)
Statement
-------------------
Going to london
Apples in Tema
Sydney is a city
China is a country
Africa is a continent
In the end I hope to see a table like this :
Statement
location
Going to london
London
Apples in Tema
Tema
Sydney is a city
Sydney
china is a country
China
Africa is a continent
Africa
By using this script,
SELECT Statement,
Case
WHEN Statement::text ~~* '%london%'::character varying::text
THEN 'london'::character varying
ELSE NULL::character varying
END AS location
FROM Table1
I think I would have to write a very tall script, but I was wondering if I could get help with something efficient and quite simple to achieve this
If you have a list of places, you can use that:
select t1.*, v.place
from table1 t1 cross join
(values ('tema'), ('london'), ('sydney'), ('germany'), ('china'), ('africa')
) v(place)
on Statement::text ilike '%' || v.place || '%';
Note: You might want to use regular expressions so you can include work boundaries but your example code doesn't do tis.
I'm trying to get cities which are equal to a particular city based off a user search I will be implementing .
I've got a sql query below which gives the exact output I want:
Select r.City, AVG(s.Longitude) AS Longitude, AVG(s.Latitude) AS Latitude
From CafeAddress r inner join Cafe s on s.CafeId = r.CafeId
Where City = 'Mumbai'
Group By City
Current output:
City Longitude Latitude
Mumbai -73.9904097 40.7036292
What I'm currently trying to add is a urlsafe "id" which is pretty much the city but with no white spaces, random chars just want it all lower case.
Like below:
id City Longitude Latitude
mumbai Mumbai -73.9904097 40.7036292
Is there a way to implement something like this?
Use LOWER to make it lowercase
Use TRIM to trim whitespace from beginning/end
Use REPLACE to replace interior spaces w/ underscore
Select REPLACE(TRIM(LOWER(r.City)),' ','_'),r.City, AVG(s.Longitude) AS Longitude, AVG(s.Latitude) AS Latitude
From CafeAddress r inner join Cafe s on s.CafeId = r.CafeId
Where City = 'Mumbai'
Group By City
Example, if r.City was ' SAN JOSE '
it would return: 'san_jose'
You can daisy chain REPLACE() to get rid of special characters or use TRANSLATE()
This is a heavily simplified version of an SQL problem I'm dealing with. Let's say I've got a table of all the cities in the world, like this:
country city
------------
Canada Montreal
Cuba Havanna
China Beijing
Canada Victoria
China Macau
I want to count how many cities each country has, so that I would end up with a table as such:
country city_count
------------------
Canada 50
Cuba 10
China 200
I know that I can get the distinct country values with SELECT distinct country FROM T1 and I suspect I need to construct a subquery for the city_count column. But my non-SQL brain is just telling me I need to loop through the results...
Thanks!
Assuming the only reason for a new row is a unique city
select country, count(country) AS City_Count
from table
group by country
How would you list the people from a database that are not from 'London'?
Say the database is:
Cust_id address
1 33 avenue, Liverpool
2 21 street 12345, London
3 469 connection ave, Manchester
I'd like to list the customers that are NOT from London. Here's what I've tried:
select Cust_id from customers where address <> 'London';
Now when I do that, it lists all the customers, regardless of location.
Help would be greatly appericated.
Not ideal but might satisfy your requirements:
select Cust_id from customers
where address NOT LIKE '% London%';
[Note the added space: it assumes you will always precede the city name with a space. '%London%' would match words containing London]
(It might be better if you had a normalised address, i.e. broken into street address, town, city, etc.))
Try this:
select Cust_id from customers where address not like '%London%';
or this:
select Cust_id from customers where not address like '%London%';
Both of these are OK.
For more details on LIKE see e.g. here: SQL LIKE