题解 | #对于employees表中，给出奇数行的first_name#

自连接

SELECT s1.emp_no, s1.salary,
(SELECT SUM(s2.salary)
FROM salaries AS s2
WHERE s2.emp_no <= s1.emp_no
AND s2.to_date = '9999-01-01') AS running_total
FROM salaries AS s1
WHERE s1.to_date = '9999-01-01'
ORDER BY s1.emp_no