SELECT department, VARIANCE(salary) AS salary_variance FROM employees GROUP BY department; 
-- Output:
department     salary_variance
------------   ---------------
Engineering     15625000.00
Marketing        9216000.00
Sales           12250000.00
HR               4840000.00
IT              11560000.00

Note: Higher variance indicates more salary spread

SELECT category, VAR_POP(price) AS price_variance FROM products GROUP BY category; 
-- Output:

category        price_variance
-------------   --------------
Electronics      125400.25
Clothing          5625.75
Books             1225.50
Accessories       2304.80
Home & Garden     8100.60
Note: Population variance of all prices in category

SELECT course_id, VAR_SAMP(score) AS score_variance FROM student_scores GROUP BY course_id;
-- Output:
course_id    course_name        score_variance
----------   -------------      --------------
CS101        Programming 101        64.50
MATH201      Statistics            89.75
ENG102       English Comp          45.25
PHYS101      Physics I            102.80
CHEM101      Chemistry            78.90

Note: Sample variance of student scores