HackerRank SQL Problems and Solutions — 1

Problem 1

Query all columns for all American cities in the CITY table with populations larger than 100000. The CountryCode for America is USA.

The CITY table is described as follows:

Figure 1. City table

Query

SELECT * 
FROM CITY 
WHERE TRUE
      AND COUNTRYCODE  = 'USA' 
      AND POPULATION > 100000;

Output

3878 Scottsdale USA Arizona 202705 
3965 Corona USA California 124966 
3973 Concord USA California 121780 
3977 Cedar Rapids USA Iowa 120758 
3982 Coral Springs USA Florida 117549 

Problem 2

Query the NAME field for all American cities in the CITY table with populations larger than 120000. The CountryCode for America is USA.

Query

SELECT NAME
FROM CITY
WHERE 0=0
      AND COUNTRYCODE = 'USA'
      AND POPULATION > 120000

Output

Scottsdale
Corona
Concord
Cedar Rapids

Problem 3

Query all columns (attributes) for every row in the CITY table.

Query

SELECT * FROM CITY

Output

6 Rotterdam NLD Zuid-Holland 593321 
3878…