logo

Back to questions

Compressed Mean Alibaba SQL Interview Question

Compressed Mean

Alibaba SQL Interview Question

You're trying to find the mean number of items per order on Alibaba, rounded to 1 decimal place using tables which includes information on the count of items in each order ( table) and the corresponding number of orders for each item count ( table).

Table:

Column NameType
item_countinteger
order_occurrencesinteger

Example Input:

item_countorder_occurrences
1500
21000
3800
41000

There are a total of 500 orders with one item per order, 1000 orders with two items per order, and 800 orders with three items per order."

Example Output:

mean
2.7

Explanation

Let's calculate the arithmetic average:

Total items =

Total orders =

Mean =

The dataset you are querying against may have different input & output - this is just an example!

Input

(PostgreSQL)

Output