Permintaan SQL untuk menghitung perubahan nilai dalam kolom

Dari Oracle 12, Anda dapat menggunakan MATCH_RECOGNIZE :

SELECT cat,
       month,
       COUNT(*)
FROM   (
  SELECT t.*,
         TRUNC( "DATE", 'MM' ) AS month
  FROM   table_name t
)
MATCH_RECOGNIZE(
  PARTITION BY cat, month
  ORDER BY "DATE", version
  ONE ROW PER MATCH
  AFTER MATCH SKIP TO LAST change_code
  PATTERN ( strt change_code )
  DEFINE
    change_code AS change_code.some_code <> strt.some_code
)
GROUP BY cat, month

Yang, untuk data sampel:

CREATE TABLE table_name ( CAT, NR, "DATE", VERSION, SOME_CODE ) AS
SELECT 'ABC',   123,    TIMESTAMP '2009-02-19 00:00:00 UTC',    1,  'OPP' FROM DUAL UNION ALL
SELECT 'ABC',   456,    TIMESTAMP '2009-03-18 00:00:00 UTC',    1,  'ZUM' FROM DUAL UNION ALL
SELECT 'ABC',   444,    TIMESTAMP '2009-03-18 00:00:00 UTC',    1,  'ZUM' FROM DUAL UNION ALL
SELECT 'ABC',   444,    TIMESTAMP '2009-03-18 00:00:00 UTC',    2,  'MUZ' FROM DUAL UNION ALL
SELECT 'ABC',   456,    TIMESTAMP '2009-04-18 00:00:00 UTC',    2,  'XXX' FROM DUAL UNION ALL
SELECT 'ABC',   456,    TIMESTAMP '2009-04-18 00:00:00 UTC',    3,  'XXX' FROM DUAL UNION ALL
SELECT 'ABC',   456,    TIMESTAMP '2009-04-18 00:00:00 UTC',    4,  'UIO' FROM DUAL UNION ALL
SELECT 'ABC',   456,    TIMESTAMP '2009-05-18 00:00:00 UTC',    5,  'RQA' FROM DUAL UNION ALL
SELECT 'DEF',   637,    TIMESTAMP '2018-02-16 00:00:00 UTC',    1,  'FAW' FROM DUAL UNION ALL
SELECT 'DEF',   789,    TIMESTAMP '2018-02-17 00:00:00 UTC',    1,  'WER' FROM DUAL UNION ALL
SELECT 'GHI',   248,    TIMESTAMP '2018-02-17 00:00:00 UTC',    1,  'QWE' FROM DUAL UNION ALL
SELECT 'GHI',   248,    TIMESTAMP '2019-02-17 00:00:00 UTC',    2,  'PPP' FROM DUAL UNION ALL
SELECT 'GHI',   357,    TIMESTAMP '2020-02-16 00:00:00 UTC',    1,  'FFF' FROM DUAL UNION ALL
SELECT 'GHI',   420,    TIMESTAMP '2020-02-16 00:00:00 UTC',    1,  'QDS' FROM DUAL UNION ALL
SELECT 'GHI',   357,    TIMESTAMP '2020-02-16 00:00:00 UTC',    2,  'GGG' FROM DUAL UNION ALL
SELECT 'GHI',   357,    TIMESTAMP '2020-02-16 00:00:00 UTC',    3,  'LLL' FROM DUAL UNION ALL
SELECT 'GHI',   357,    TIMESTAMP '2020-02-16 00:00:00 UTC',    4,  'LLL' FROM DUAL UNION ALL
SELECT 'GHI',   357,    TIMESTAMP '2020-08-16 00:00:00 UTC',    4,  'FFF' FROM DUAL UNION ALL
SELECT 'GHI',   357,    TIMESTAMP '2020-10-16 00:00:00 UTC',    5,  'ZZZ' FROM DUAL

Keluaran:

Jika Anda ingin melihat perubahannya, Anda dapat menggunakan:

SELECT *
FROM   (
  SELECT t.*,
         TRUNC( "DATE", 'MM' ) AS month
  FROM   table_name t
)
MATCH_RECOGNIZE(
  PARTITION BY cat, month
  ORDER BY "DATE", version
  MEASURES
    MATCH_NUMBER()     AS mn,
    FIRST( some_code ) AS change_from,
    LAST( some_code )  AS change_to
  ONE ROW PER MATCH
  AFTER MATCH SKIP TO LAST change_code
  PATTERN ( strt change_code )
  DEFINE
    change_code AS change_code.some_code <> strt.some_code
)

Keluaran mana:

db<>fiddle di sini

Jika persyaratan Anda untuk "dalam satu bulan" adalah Anda menginginkan perubahan di mana ada perbedaan paling banyak satu bulan antara baris sebelumnya dengan baris yang diubah, bahkan jika baris berada dalam dua bulan kalender yang berbeda, (bukan hanya perubahan yang terjadi di bulan kalender yang sama) maka Anda dapat menggunakan:

SELECT cat,
       TRUNC( change_date, 'MM' ) AS month,
       COUNT(*)
FROM   table_name
MATCH_RECOGNIZE(
  PARTITION BY cat
  ORDER BY "DATE", version
  MEASURES
    LAST( "DATE" ) AS change_date
  ONE ROW PER MATCH
  AFTER MATCH SKIP TO LAST change_code
  PATTERN ( strt change_code )
  DEFINE
    change_code AS (
      change_code.some_code <> strt.some_code
      AND MONTHS_BETWEEN( change_code."DATE", strt."DATE" ) <= 1
    )
)
GROUP BY cat, TRUNC( change_date, 'MM' )

Keluaran mana:

db<>fiddle di sini