Please list the social security numbers of the male employees with a salary of over $70,000 a year.
social security numbers refers to ssn; male employees refers to gender = 'M'; salary of over $70,000 a year refers to salary > '70000'
SELECT ssn FROM employee WHERE gender = 'M' AND CAST(REPLACE(SUBSTR(salary, 4), ',', '') AS REAL) > 70000