Readers Who Never Checked Out a Book
Problem
Table: `Reader`
```text
+-----------+---------+
| Column | Type |
+-----------+---------+
| reader_id | int |
| name | varchar |
+-----------+---------+
reader_id is the primary key. Each row is one library member.
```
Table: `Checkout`
```text
+-------------+---------+
| Column | Type |
+-------------+---------+
| checkout_id | int |
| reader_id | int |
+-------------+---------+
checkout_id is the primary key. Each row records that a reader checked
out a book.
```
Write a query that returns the name of every reader who has never checked out a book. Use the column heading `Reader`.
Return the rows in any order.
**Example**
```text
Reader: Checkout:
+-----------+--------+ +-------------+-----------+
| reader_id | name | | checkout_id | reader_id |
+-----------+--------+ +-------------+-----------+
| 1 | Tamar | | 1 | 3 |
| 2 | Noa | | 2 | 1 |
| 3 | Eli | +-------------+-----------+
| 4 | Yael |
+-----------+--------+
Output:
+--------+
| Reader |
+--------+
| Noa |
| Yael |
+--------+
```
Noa and Yael have no rows in `Checkout`, so they have never checked out a book.
Tables
Example rows — the live problem includes the full dataset.
| reader_id | name |
|---|---|
| 1 | Tamar |
| 2 | Noa |
| 3 | Eli |
| checkout_id | reader_id |
|---|---|
| 1 | 3 |
| 2 | 1 |
Expected output
Your answer should return 2 rows with the columns Reader.
Starter code (SQL)
SELECT *
FROM Reader;Solve this SQL question free
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Solution & explanation
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