Let’s do a quick practice exercise to make sure the idea of WHERE is crystal clear.

Once again, we are working with a table called phones.

Each row in this table represents a different phone and contains information like:

• phone name

• manufacturer

• price

• units sold

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🎯 Goal of This Exercise

Write a SQL query that will:

• print the name

• and price

• of every phone that sold more than 5000 units

In simple words:

We only want phones where units_sold is greater than 5000.

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🧠 How to Think About It

Ask yourself these questions:

1. Which table am I selecting from?
   → phones

2. Which columns do I want to display?
   → name, price

3. What condition should filter the rows?
   → units_sold > 5000

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✍️ Your Task

Try writing the SQL query yourself before looking at the solution.

Use what you’ve learned:

• SELECT to choose columns

• FROM to choose the table

• WHERE to filter rows

Take a moment and give it a try 👇

(If you get stuck, no stress — we’ll walk through the solution next.)

Solution: Filtering with WHERE

Let’s walk through the solution step by step and make sure everything makes sense.

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Step 1: Decide What We’re Doing

We are retrieving data from the database, so we know our query must start with the SELECT keyword.

From the problem statement, we want:

• the name

• and the price
  of phones

So we begin with:

select name, price

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Step 2: Decide Where the Data Comes From

All of this data lives inside the phones table.

So next, we add:

from phones

At this point, if we stopped here, PostgreSQL would return all phones — but that’s not what we want.

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Step 3: Filter the Rows

The requirement was very clear:

Only include phones that sold more than 5000 units

So we use the WHERE clause to filter rows based on the units_sold column.

where units_sold > 5000

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✅ Final Query

Putting everything together, the final query looks like this:

select name, price
from phones
where units_sold > 5000;

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✅ Result

When we run this query:

• PostgreSQL first looks at the phones table

• filters rows where units_sold is greater than 5000

• and finally returns only the name and price columns

The output shows only the phones that meet the condition — exactly what we wanted.

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Key Takeaway

• SELECT decides which columns

• FROM decides which table

• WHERE decides which rows

You’re now officially comfortable filtering rows using WHERE 🎉