DO Recruitment Pre - Interview Exercise | Take the Quiz

This exercise is meant to examine your analytical thinking skills, your programming proficiency, database query skills and general knowledge in current technologies. Read through the questions carefully before answering.

The following section consists of logical problems. Read carefully before answering.

There are three boxes. One is labeled APPLES, another is labeled ORANGES and the third is labeled APPLES AND ORANGES. You know that all three boxes are labeled incorrectly. You may ask me to pick a fruit from any of the boxes, after which you should be able to re-label all the boxes correctly. Which would you choose from?

APPLES

ORANGES

APPLES AND ORANGES

ANY

Adwoa has 12 black socks and 12 white socks in her drawer. In complete darkness and without looking, how many socks must she take from the drawer in order to be sure to get a pair that match?

A frog is at the bottom of a 30 metre well. Each day, it gathers enough energy to for a single 3 metre jump up then well. Exhausted, it then hangs there for the rest of the day. At night, while it sleeps, it slips 2 metres back down. How many days does it take to get out of the well? NOTE: Assume after the first leap its hind legs are exactly 3 metres up the well. Its hind legs must clear the edge of the well for it to escape?

An ecommerce application stores users’ orders in a database. An order can contain multiple items, each having a name, item code, quantity and unit price. Likewise, a user can have multiple orders. A section of the database is shown in the diagram. Using the diagram as reference, choose the queries that will give you the information required in the next four questions.

The total number of items customer number 1 has ordered

Select quantity from order_items, `order` where order.customer_no = 1

Select count(`order`.order_no) from order_items, `order` where order.customer_no = 1

Select count(quantity) from order_items, `order` where order.customer_no = 1

Select sum(quantity) from order_items, `order` where order.customer_no = 1

The total value of all customer 1’s orders

Select sum(unit_cost) from order_items, `order` where order.customer_no = 1

Select count(unit_cost) from order_items, `order` where order.customer_no = 1

Select sum(unit_cost * quantity) from order_items, `order` where order.customer_no = 1

Select count(unit_cost * quantity) from order_items, `order` where order.customer_no = 1

The most popular item (most ordered item) across all customers.

Select item_code, quantity from order_items group by item_code order by quantity desc limit 0, 1

Select item_code, count(quantity) from order_items group by item_code order by count(quantity) desc limit 0, 1

Select item_code, sum(quantity) from order_items group by item_code order by sum(quantity) desc limit 0, 1

Select item_code, sum(quantity) from order_items group by item_code order by count(quantity) desc limit 0, 1

The item that has generated the most revenue across all customers

Select item_code, sum(unit_cost) from order_items group by item_code order by sum(unit_cost) desc limit 0, 1

Select item_code, count(unit_cost) from order_items group by item_code order by count(unit_cost) desc limit 0, 1

Select item_code, count(unit_cost * quantity) from order_items group by item_code order by count(unit_cost * quantity) desc limit 0, 1

Select item_code, sum(unit_cost * quantity) from order_items group by item_code order by sum(unit_cost * quantity) desc limit 0, 1

Which of the following statements is true (incorrect answers attract a negative score)

All APIs are interfaces

All APIs are web services

All web services are APIs

ReST and SOAP are web service technologies

Which of the following allow one application to directly access the functionality of another (incorrect answers attract a negative score)

Web services

SDKs

Databases

Files

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