特定员工的最大日期与倒数第二个最大日期之间的差异- postgresql

SELECT MAX(date_column) AS max_date, 
       (SELECT MAX(date_column) 
        FROM table_name 
        WHERE employee_id = 'specific_employee_id' 
          AND date_column < (SELECT MAX(date_column) FROM table_name WHERE employee_id = 'specific_employee_id')
       ) AS second_max_date
FROM table_name
WHERE employee_id = 'specific_employee_id';

SELECT DATE_PART('day', max_date - second_max_date) AS date_diff
FROM (
  SELECT MAX(date_column) AS max_date, 
         (SELECT MAX(date_column) 
          FROM table_name 
          WHERE employee_id = 'specific_employee_id' 
            AND date_column < (SELECT MAX(date_column) FROM table_name WHERE employee_id = 'specific_employee_id')
         ) AS second_max_date
  FROM table_name
  WHERE employee_id = 'specific_employee_id'
) AS subquery;