Summary  
This chapter covers using the WHERE clause to filter rows in a SELECT statement based on specified conditions and ensuring the ORDER BY clause follows WHERE.  

General domain of usage  
Data retrieval from relational databases

In databases, tables typically hold substantial volumes of data. However, frequently we're interested in retrieving specific portions of the data rather than the entirety. To accomplish this, we need to define the conditions for data retrieval, which are referred to as filtering criteria.

Data is filtered using a `WHERE` clause specifying the search criteria in a `SELECT` statement. The `WHERE` clause appears immediately after the table name.

When specifying a string value, such as a country name, we need to enclose the text in single quotes (`'`).



SELECT name, continent 
FROM country 
WHERE continent='Europe';

The `SELECT` statement gets 2 columns from the `country` table and returns only rows with the continent value `'Europe'`.

### Clause Position

When we use the `ORDER BY` and `WHERE` clauses, we ensure the `ORDER BY` comes after the `WHERE` clause. 



SELECT capital, continent 
FROM country 
WHERE continent='Asia'
ORDER BY continent DESC;

Which clause is used to filter rows in a SQL SELECT statement?

In which position should the WHERE clause appear in a SELECT statement when combined with ORDER BY?

This course is perfect for beginners ready to explore the world of SQL. Whether you're just starting out in database management or aiming to use SQL for your application development projects, this course covers the essentials. You'll quickly learn how to leverage the full potential of SQL, from querying and managing data to seamlessly integrating it into real-world applications. By the end of the course, you'll have the confidence and skills to solve practical problems with SQL and enhance your development process.

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.

In this section, we’ll explore how to organize and prioritize the data returned by a query using the ORDER BY clause. Placed at the end of a SELECT statement, this clause lets you sort your results by one or multiple columns, either in ascending or descending order, enabling more meaningful and easily interpretable data output.

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.

In this section, we’ll explore how to refine your search conditions by combining WHERE clauses with the AND and OR operators. We’ll also cover how the NOT operator can be used to exclude certain results.

In this section, we will learn what the SQL aggregate functions are and how to use them to summarize table data.

Using the WHERE Clause

Clause Position

1. Which clause is used to filter rows in a SQL SELECT statement?

2. In which position should the WHERE clause appear in a SELECT statement when combined with ORDER BY?