Introduction to SQL

1. Retrieving Data

In this section, we will learn how to use the SQL SELECT statement to get a single table column, multiple table columns, and all table columns. We will also find out how to return unique values.

Retrieving Individual Columns

Retrieving Multiple Columns

Retrieving All Columns

Retrieving Distinct Rows

Limiting Results

Challenge: Find the Population of the Countries

Challenge: Find All Countries

Challenge: Find All Countries With Their IDs

Challenge: Find Country Capitals

Challenge: Find the Regions in Which All Countries Are Located

2. Sorting Retrieved Data

In this section, we will learn how to sort retrieved data using the ORDER BY clause. This clause, which must be the last in the SELECT statement, can be used to sort data on one or more columns as needed.\n

Sorting Data

Challenge: Population Sort

Sorting by Multiple Columns

Challenge: Dual-Sort Query

Specifying Sort Direction

Challenge: Sort the Countries by Region and Capital

Challenge: Sort Capitals in Descending Order

Challenge: Sort Countries in Ascending Order

Challenge: Find Countries, Their IDs, and Their Populations

Challenge: Find Countries, IDs, Populations, Regions, and Sort Them

Challenge: Find All Continents and Sort Them in Ascending Order

3. Filtering Data

In this section, we will learn how to filter returned data using the SELECT statement’s WHERE clause. We will learn how to test for equality, inequality, more and less significant than value ranges, and NULL values.

Using the WHERE Clause

Challenge: North America Population Sort

The WHERE Clause Operators

Challenge: Population Threshold Query

Checking for a Range of Values

Checking for NO Value

4. Advanced Data Filtering

In this section, we will learn how to combine WHERE clauses with the AND and OR operators. We will also find out how the NOT operator works.\n\n\n

Using the AND Operator

Challenge: Europe Region Sort

Using the OR operator

Challenge: America Regions Filter