# Difference between revisions of "Helpdesk Hard Questions"

## Hard

Show the manager and number of calls received for each hour of the day on 2017-08-12

```+---------+---------------+----+
| Manager | Hr            | cc |
+---------+---------------+----+
| LB1     | 2017-08-12 08 |  6 |
| LB1     | 2017-08-12 09 | 16 |
| LB1     | 2017-08-12 10 | 11 |
| LB1     | 2017-08-12 11 |  6 |
| LB1     | 2017-08-12 12 |  8 |
| LB1     | 2017-08-12 13 |  4 |
| AE1     | 2017-08-12 14 | 12 |
| AE1     | 2017-08-12 15 |  8 |
| AE1     | 2017-08-12 16 |  8 |
| AE1     | 2017-08-12 17 |  7 |
| AE1     | 2017-08-12 19 |  5 |
+---------+---------------+----+
```

80/20 rule. It is said that 80% of the calls are generated by 20% of the callers. Is this true? What percentage of calls are generated by the most active 20% of callers.

Note - Andrew has not managed to do this in one query - but he believes it is possible.

```+---------+
| t20pc   |
+---------+
| 32.2581 |
+---------+
```

Annoying customers. Customers who call in the last five minutes of a shift are annoying. Find the most active customer who has never been annoying.

```+--------------+------+
| Company_name | abna |
+--------------+------+
| High and Co. |   20 |
+--------------+------+
```

Maximal usage. If every caller registered with a customer makes a call in one day then that customer has "maximal usage" of the service. List the maximal customers for 2017-08-13.

```+-------------------+----+----+
| company_name      | sc | cc |
+-------------------+----+----+
| Askew Inc.        |  2 |  2 |
| Bai Services      |  2 |  2 |
| Dasher Services   |  3 |  3 |
| High and Co.      |  5 |  5 |
| Lady Retail       |  4 |  4 |
| Packman Shipping  |  3 |  3 |
| Pitiable Shipping |  2 |  2 |
| Whale Shipping    |  2 |  2 |
+-------------------+----+----+
```

Consecutive calls occur when an engineer deals with two callers within 10 minutes. Find the longest sequence of consecutive calls – give the name of the operator and the first and last call date in the sequence.