Introduction
Multiple metrics for a single object
Metrics for two groups
Ratios and percentages
Global vs. specific metrics
Instruction
Perfect! Now,we'll add a third column to our query:
SELECT
COUNT(CASE
WHEN shipped_date IS NOT NULL
THEN order_id
END) AS count_shipped,
COUNT(order_id) AS count_all,
COUNT(CASE
WHEN shipped_date IS NOT NULL
THEN order_id
END) / CAST(COUNT(order_id) AS decimal) AS shipped_ratio
FROM orders;
In the third column, we calculate the ratio by dividing the expression from the first column by the expression from the second column. However, both of these values are integers, so we need to force SQL to use floating-point division. To do that, we cast one of the metrics to the decimal data type: CAST(COUNT(order_id) AS decimal).
Exercise
Add a third column to the template code: discounted_ratio. It should contain the ratio of discounted line items (from column 1) to all line items (from column 2).
Stuck? Here's a hint!
Remember to use CAST(... AS decimal) for floating-point division.
