Course Content
Introduction to SQL
1. Retrieving Data
Retrieving Individual ColumnsRetrieving Multiple Columns Retrieving All ColumnsRetrieving Distinct RowsLimiting ResultsChallenge: Find the Population of the CountriesChallenge: Find All CountriesChallenge: Find All Countries With Their IDsChallenge: Find Country CapitalsChallenge: Find the Regions in Which All Countries Are Located
2. Sorting Retrieved Data
Sorting DataChallengeSorting by Multiple ColumnsChallengeSpecifying Sort DirectionChallenge: Sort the Countries by Region and CapitalChallenge: Sort Capitals in Descending OrderChallenge: Sort Countries in Ascending OrderChallenge: Find Countries, Their IDs, and Their PopulationsChallenge: Find Countries, IDs, Populations, Regions, and Sort ThemChallenge: Find All Continents and Sort Them in Ascending Order
4. Advanced Data Filtering
Introduction to SQL
Using the AND Operator
To filter on multiple columns, you must use the AND
operator to add conditions to the WHERE
clause. Let's see an example:
This request retrieves only those rows that correspond to both conditions: countries where the population is greater than or equal to 1,000,000 and the continent is Europe.
Task
From the country
table, retrieve only countries' names (column name
) from Asia
(can be checked in column continent
) with a population greater than 1000000
(can be checked in column population
). Please note you only need to output country names.
Here's a short example of the country
table:
id | name | continent | region | surfacearea | capital | population |
1 | Japan | Asia | Eastern Asia | 377829 | Tokyo | 126714000 |
2 | Latvia | Europe | NULL | 64589 | Riga | 2424200 |
3 | Mexico | North America | Central America | 1958201 | Mexico City | 98881000 |
... | ... | ... | ... | ... | ... | ... |
15 | Malta | Europe | Southern Europe | 316 | Valletta | 380200 |
Everything was clear?
Section 4. Chapter 1