cohort ret ?

WITH base_query AS (
  SELECT
    emp_no,
    start_date,
    end_date,
    DATE_FORMAT(start_date, '%Y') AS cohort, DATEDIFF(end_date, start_date) / 365.25 AS tenure
  FROM dept_emp WHERE start_date BETWEEN '1985-01-01' AND '1995-12-31'
),
grouped_query AS (
  SELECT
    cohort,
    COUNT(emp_no) AS total_employees,
    SUM(IF(tenure >= 1, 1, 0)) AS year_1,
    SUM(IF(tenure >= 2, 1, 0)) AS year_2,
    SUM(IF(tenure >= 3, 1, 0)) AS year_3,
    SUM(IF(tenure >= 4, 1, 0)) AS year_4,
    SUM(IF(tenure >= 5, 1, 0)) AS year_5,
    SUM(IF(tenure >= 6, 1, 0)) AS year_6,
    SUM(IF(tenure >= 7, 1, 0)) AS year_7,
    SUM(IF(tenure >= 8, 1, 0)) AS year_8,
    SUM(IF(tenure >= 9, 1, 0)) AS year_9,
    SUM(IF(tenure >= 10, 1, 0)) AS year_10
    FROM base_query GROUP BY cohort
)
SELECT
  cohort,
  total_employees, year_1, year_2, year_3, year_4, year_5, year_6, year_7, year_8, year_9, year_10,
  concat((year_1 / total_employees * 100),'%') AS retention_1,
  concat((year_2 / total_employees * 100),'%') AS retention_2,
  concat((year_3 / total_employees * 100),'%') AS retention_3,
  concat((year_4 / total_employees * 100),'%') AS retention_4,
  concat((year_5 / total_employees * 100),'%') AS retention_5,
  concat((year_6 / total_employees * 100),'%') AS retention_6,
  concat((year_7 / total_employees * 100),'%') AS retention_7,
  concat((year_8 / total_employees * 100),'%') AS retention_8,
  concat((year_9 / total_employees * 100),'%') AS retention_9,
  concat((year_10 / total_employees * 100),'%') AS retention_10
FROM
  grouped_query
ORDER BY
  cohort ASC;