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-- Show all book titles from the checkout history (including duplicates)
SELECT title
FROM book_checkouts;

-- Show only unique book titles
SELECT DISTINCT title
FROM book_checkouts;

-- Rename columns in the output for clarity
SELECT title AS book_title, member_id AS borrower
FROM book_checkouts;

-- Combine DISTINCT with alias
SELECT DISTINCT title AS unique_title
FROM book_checkouts;

# `DISTINCT` and Aliases

SQL provides tools to clean your results and make column names easier to read.

The `DISTINCT` keyword removes **duplicate values**, while the `AS` keyword assigns temporary names — called **aliases** — to columns or tables.

<br/>

## `DISTINCT`: Remove Duplicate Values

The `DISTINCT` keyword is used in the `SELECT` clause to return only **unique values**.

```sql title="Remove duplicate book titles"
SELECT DISTINCT title
FROM book_checkouts;
```

If the same book has been checked out multiple times, this will show each title only once.

<br/>

## `AS`: Rename Columns and Tables

The `AS` keyword allows you to *assign an alias*, a temporary name, to a column or table in your query.

```sql title="Rename columns for clarity"
SELECT title AS book_title, member_id AS borrower
FROM book_checkouts;
```

In the result, column headers will appear as `book_title` and `borrower` instead of `title` and `member_id`.

DISTINCT filters out repeated values, showing each unique value only once.

DISTINCT and Aliases

DISTINCT: Remove Duplicate Values

AS: Rename Columns and Tables

`DISTINCT` and Aliases

`DISTINCT`: Remove Duplicate Values

`AS`: Rename Columns and Tables