SelectQueryII.sql

-- Question link - https://www.hackerrank.com/challenges/revising-the-select-query-2/problem?isFullScreen=true
-- Language: T-SQL
-- Database: MySQL/PostgreSQL/SQL Server compatible

/*
Problem: Revising the Select Query II
Query the NAME field for all American cities in the CITY table with populations larger than 120000. 
The CountryCode for America is USA.

Table Schema:
CITY
- ID (INTEGER)
- NAME (VARCHAR2)
- COUNTRYCODE (CHAR(3))  
- DISTRICT (VARCHAR2)
- POPULATION (INTEGER)

Input Format:
The CITY table is described as follows:
Field       | Type
------------|----------
ID          | NUMBER
NAME        | VARCHAR2(17)
COUNTRYCODE | CHAR(3)
DISTRICT    | VARCHAR2(20)
POPULATION  | NUMBER
*/

-- Solution:
SELECT name FROM city
WHERE (population > 120000) AND countryCode="USA";

/*
Explanation:
- SELECT name: Only retrieves the NAME column instead of all columns
- FROM city: Specifies the CITY table as the data source
- WHERE clause applies two filtering conditions:
  1. population > 120000 (cities with more than 120,000 people)
  2. countryCode="USA" (only American cities)
- AND operator ensures both conditions must be satisfied
- Result: Names of large American cities with population exceeding 120,000

Expected Output:
Returns a single column containing city names that meet the criteria.

Sample cities that might be returned:
- New York
- Los Angeles  
- Chicago
- Houston
- Phoenix
*/