Dari Oracle 12, ini adalah jenis masalah yang MATCH_RECOGNIZE
dimaksudkan untuk memecahkan:
SELECT *
FROM table_name
MATCH_RECOGNIZE (
PARTITION BY Emp_ID
ORDER BY dt
MEASURES
FIRST(dt) AS min_date,
LAST(dt) AS max_date,
MATCH_NUMBER() AS group_number
PATTERN (one+)
DEFINE
one AS dummy = 1
)
Yang, untuk data sampel:
CREATE TABLE table_name ( dt, Emp_ID, Dummy ) AS
SELECT DATE '2021-01-01', 5, 1 FROM DUAL UNION ALL
SELECT DATE '2021-01-02', 5, 1 FROM DUAL UNION ALL
SELECT DATE '2021-01-03', 5, 1 FROM DUAL UNION ALL
SELECT DATE '2021-01-04', 5, 1 FROM DUAL UNION ALL
SELECT DATE '2021-01-05', 5, 0 FROM DUAL UNION ALL
SELECT DATE '2021-01-06', 5, 1 FROM DUAL UNION ALL
SELECT DATE '2021-01-07', 5, 1 FROM DUAL UNION ALL
SELECT DATE '2021-01-01', 8, 1 FROM DUAL UNION ALL
SELECT DATE '2021-01-02', 8, 1 FROM DUAL UNION ALL
SELECT DATE '2021-01-03', 8, 1 FROM DUAL UNION ALL
SELECT DATE '2021-01-04', 8, 0 FROM DUAL UNION ALL
SELECT DATE '2021-01-05', 8, 0 FROM DUAL UNION ALL
SELECT DATE '2021-01-06', 8, 0 FROM DUAL UNION ALL
SELECT DATE '2021-01-07', 8, 1 FROM DUAL;
Keluaran:
db<>fiddle di sini