The goal of my query is to return the country name and its head of state if it's headofstate has a name starting with A, and the capital of the country has greater than 100,000 people utilizing a nested query.
Here is my query:
SELECT country.name as country,
(SELECT country.headofstate
from country
where country.headofstate like 'A%')
from country, city
where city.population > 100000;
I've tried reversing it, placing it in the where clause etc. I don't get nested queries. I'm just getting errors back, like "subquery returns more than one row" and such. If someone could help me out with how to order it, and explain why it needs to be a certain way, that'd be great.
You need to join
the two tables and then filter the result in where
clause:
SELECT country.name as country, country.headofstate
from country
inner join city on city.id = country.capital
where city.population > 100000
and country.headofstate like 'A%'
Query below should help you achieve what you want.
select scountry, headofstate from data
where data.scountry like 'a%'and ttlppl>=100000
The way I see it, the only place for a nested query would be in the WHERE clause, so e.g.
SELECT country.name, country.headofstate
FROM country
WHERE country.headofstate LIKE 'A%' AND
country.id in (SELECT country_id FROM city WHERE population > 100000)
Apart from that, I have to agree with Adrian on: why the heck should you use nested queries?
Source: Stackoverflow.com