﻿ SQL Formatting Output: Find largest number of orders booked by the customer - w3resource

# SQL Exercises: Find the largest number of orders booked by the customer

## SQL Formatting Output: Exercise-9 with Solution

From the following table, write a SQL query that counts the unique orders and the highest purchase amount for each customer. Sort the result-set in descending order on 2nd field. Return customer ID, number of distinct orders and highest purchase amount by each customer.

Sample table: orders

Sample Solution:

``````SELECT customer_id, COUNT(DISTINCT ord_no),
MAX(purch_amt)
FROM orders
GROUP BY customer_id
ORDER BY 2 DESC;``````

Output of the Query:

```customer_id	count		max
3002		3		5760.00
3009		2		2480.40
3005		2		948.50
3004		1		1983.43
3001		1		270.65
3007		1		2400.60
3008		1		250.45
3003		1		75.29
```

Relational Algebra Expression:

Relational Algebra Tree:

Explanation:

Pictorial presentation:

## Query Visualization:

Duration:

Rows:

Cost:

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How to restore a dump file from mysqldump?

It should be as simple as running this:

```mysql -u <user> -p < db_backup.dump
```

If the dump is of a single database you may have to add a line at the top of the file:

```USE <database-name-here>;
```

Ref: https://bit.ly/3xKmyw2