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Introduction to SQL
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Kursinnehåll

Introduction to SQL

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 DataChallenge: Population SortSorting by Multiple ColumnsChallenge: Dual-Sort QuerySpecifying 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
3. Filtering Data
Using the WHERE ClauseChallenge: North America Population SortThe WHERE Clause Operators Challenge: Population Threshold QueryChecking for a Range of ValuesChecking for NO Value
4. Advanced Data Filtering
Using the AND OperatorChallenge: Europe Region SortUsing the OR operatorChallenge: America Regions FilterUsing the NOT OperatorChallenge: Non-Europe Capitals Sort
5. Aggregate Functions
The AVG() FunctionChallenge: Surface Area SelectionThe COUNT() FunctionChallenge: Continental CountThe MAX() FunctionThe MIN() FunctionChallenge: Large Surface Area AverageThe SUM() Function

book
The WHERE Clause Operators

SQL supports a lot of conditional statements.

Less Than

Let’s look at the examples:
This example lists all countries that have a population of less than 2424200:


              
123

            
SELECT name, population
FROM country
WHERE population < 2424200;
copy

Less Than or Equal to

The following example retrieves all countries with a population less than or equal to 2424200:


              
123

            
SELECT name, population
FROM country
WHERE population <= 2424200;
copy

Not Equal

The following example retrieves all non-Asian countries:


              
123

            
SELECT name, continent
FROM country
WHERE continent<>'Asia';
copy

Here is the country table we are working with:

Uppgift

Swipe to start coding

Write an SQL query to retrieve the name, population, region, and capital columns from the country table (please retrieve these columns in this order), returning only the countries with a region named Southern Europe.

Lösning

Switch to desktopByt till skrivbordet för praktisk övningFortsätt där du är med ett av alternativen nedan
Var allt tydligt?

Hur kan vi förbättra det?

Tack för dina kommentarer!

Avsnitt 3. Kapitel 3
toggle bottom row

book
The WHERE Clause Operators

SQL supports a lot of conditional statements.

Less Than

Let’s look at the examples:
This example lists all countries that have a population of less than 2424200:


              
123

            
SELECT name, population
FROM country
WHERE population < 2424200;
copy

Less Than or Equal to

The following example retrieves all countries with a population less than or equal to 2424200:


              
123

            
SELECT name, population
FROM country
WHERE population <= 2424200;
copy

Not Equal

The following example retrieves all non-Asian countries:


              
123

            
SELECT name, continent
FROM country
WHERE continent<>'Asia';
copy

Here is the country table we are working with:

Uppgift

Swipe to start coding

Write an SQL query to retrieve the name, population, region, and capital columns from the country table (please retrieve these columns in this order), returning only the countries with a region named Southern Europe.

Lösning

Switch to desktopByt till skrivbordet för praktisk övningFortsätt där du är med ett av alternativen nedan
Var allt tydligt?

Hur kan vi förbättra det?

Tack för dina kommentarer!

Avsnitt 3. Kapitel 3
Switch to desktopByt till skrivbordet för praktisk övningFortsätt där du är med ett av alternativen nedan
Vi beklagar att något gick fel. Vad hände?
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