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Each Salary's Share of Payroll
Finance is building a payroll breakdown and needs what percentage of the total payroll each employee accounts for.
Show name, salary, and pct_of_payroll (the employee's salary as a percentage of the sum of all salaries, rounded to 2 decimals). Order by salary descending, then name.
The new idea: a window function is just a value, so you can use it inside an expression. salary * 100.0 / SUM(salary) OVER () divides each row by the whole-table total. Use 100.0 and not 100 — integer division would floor every result to 0. This "% of total" shape is behind almost every revenue-share report you'll ever write.
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Schema
employees
| emp_id | name | department | position | salary | hire_date | manager_id | performance_rating |
|---|---|---|---|---|---|---|---|
| 1 | Alice Johnson | Engineering | Senior Developer | 95000 | 2019-03-15 | 5 | 4.5 |
| 2 | Bob Smith | Engineering | Developer | 75000 | 2020-06-01 | 1 | 3.8 |
| 3 | Carol Williams | Marketing | Marketing Manager | 85000 | 2018-09-20 | NULL | 4.2 |
Expected output: pct_of_payroll = 3.16
Hint
SELECT, Window Functions, SUM, and open the hint there if you stall.Concepts
SELECT Window Functions SUM ROUND
Practise the topic: SQL practice questions · Window function practice · GROUP BY exercises
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