What is PERCENTILE_CONT and what does it return?

PERCENTILE_CONT is an SQL analytical function that calculates the continuous percentile for a given data set. It takes a percentile value (e.g., 0.5 for the median) and returns the value corresponding to that percentile, interpolating between values if necessary.

For example, if you have a set of numbers and want to find the 90th percentile, PERCENTILE_CONT(0.9) will return the value below which 90% of the data falls. This is useful for analyzing data distribution and determining threshold values.

Example of usage in SQL:

SELECT PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY salary) AS median_salary
FROM employees;

This query will return the median salary in the employees table.