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Find the Rows That Matter

Find the Rows That Matter

Filter data using WHERE conditions.

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You’ve learned to pick columns. Now it’s time to filter rows, so you only see the data you care about.

Goal

You’ll aim to:

  • Use WHERE to filter data.

  • Add simple conditions to your query.

Tables

Let’s use the following table in this lesson:

The people table

ID

Name

Age

City

1

Aisha

30

Karachi

2

Dan

24

New York

3

Fatima

27

Lahore

4

Lee

22

Seoul

Basic WHERE clause

Let’s say you only want people from Karachi. We used where to add a condition to your query.

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SELECT * FROM people WHERE city = 'Karachi';

Only shows rows where the city is 'Karachi'.

Nice! You just filtered your results to only show rows where the city is 'Karachi'.

Numeric filtering

You can also filter based on numbers using comparison operators. Let’s find people older than 25 and show just their names and ages:

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SELECT name, age FROM people WHERE age > 25;

Use comparison operators with numbers.

Great! You just learned a condition with a numeric comparison.

Using WHERE operators

  • =: Equals

  • >: Greater than

  • <: Less than

  • >= and <=: Greater than or equal to/Less than or equal to

  • !=: Not equal

Mini challenge

Show all pets that are younger than four years old:

The pets table

ID

Name

Type

Age

1

Coco

dog

5

2

Luna

cat

3

3

Goldie

fish

1

Use the above table to write your query:

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# Write your query here:

Should show Luna (3) and Goldie (1).

If you’re stuck, click the “Show Solution” button.

Great! You just combined filtering with comparison.

Tips

  • Strings go in single quotes.

  • Numbers don’t need quotes.

  • The WHERE clause works with any column.

What’s next?

Let’s get smarter with multiple conditions using AND, OR, and NOT!