[Mysql] 최근 근로내역가져오기 

SELECT
    employee_key,
    hyunjang_key,
    MIN(month) AS start_month,
    MAX(month) AS end_month,
    COUNT(*) AS consecutive_months
FROM (
         SELECT
             employee_key,
             hyunjang_key,
             month,
             DATEDIFF(month, '2000-01-01') - ROW_NUMBER() OVER (PARTITION BY employee_key, hyunjang_key ORDER BY month) AS grp
         FROM
             kongsu
         WHERE
                 employee_key = '3660'
           AND delete_YN = '0'
     ) AS subquery
GROUP BY
    employee_key,
    hyunjang_key,
    grp
ORDER BY
    employee_key,
    hyunjang_key,
    start_month;

해석

select
       hyunjang_key, employee_key ,ROW_NUMBER() OVER (PARTITION BY employee_key, hyunjang_key ORDER BY DATE_FORMAT(month, '%Y-%m')) as grp
from kongsu where employee_key ='3658' and delete_YN = '0'

아래과같이 hyunjang_key, employee_key 로 묶어서 그룹핑한다.현장별, 일한달을 그룹핑한다.