SQL Server 2019

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CREATE TABLE a1111
    ([PMM] int, [ORDER_NO] varchar(6), [MKQTY] int)
;
    
INSERT INTO a1111
    ([PMM], [ORDER_NO], [MKQTY])
VALUES
    (10905, '4N0241', 250),
    (10905, '4N0301', 375),
    (10905, '4N0292', 3700),
    (10905, '4N0331', 1335),
    (10905, '4N0341', 365),
    (10906, '5N3234', 1425),
    (10906, '5N3245', 7400),
    (10906, '5N0271', 1075),
    (10906, '5N0284', 1200),
    (10906, '5N3251', 4000),
    (10907, '6N3191', 2800),
    (10907, '6N3103', 8800),
    (10907, '6N0371', 1200),
    (10907, '6N3194', 1540),
    (10907, '6N3104', 2250),
    (10908, '7N3229', 10160),
    (10908, '7N0202', 1025),
    (10908, '7N0251', 6600),
    (10908, '7N0221', 1400),
    (10908, '7N3283', 3400),
    (10908, '8N3215', 1890),
    (10908, '8N3222', 9525),
    (10908, '8N0151', 7575),
    (10909, '8N0121', 11550),
    (10909, '9N3011', 7900),
    (10909, '8N0121', 660),
    (10909, '8N0201', 1515),
    (10909, '9N3011', 2600),
    (10909, '8N0211', 295),
    (10909, '9N3012', 10500),
    (10909, '8N3231', 8230),
    (10909, '9N3013', 2250),
    (10909, '9N3014', 2650),
    (10910, '9N0131', 7000),
    (10910, '9N0341', 5170),
    (10910, '9N3244', 1535),
    (10910, '9N3245', 1235),
    (10911, 'AN3226', 715),
    (10911, 'AN3223', 695),
    (10911, 'AN3251', 6015),
    (10911, 'AN3197', 4600),
    (10911, 'AN3222', 685),
    (10911, 'AN3231', 1535),
    (10912, 'BN3223', 1825),
    (10912, 'BN3227', 1535),
    (10912, 'BN3226', 5075),
    (10912, 'BN0291', 200),
    (10912, 'BN3224', 325),
    (10912, 'BN3221', 1115),
    (10912, 'BN3225', 1550),
    (10912, 'BN3244', 525),
    (11001, 'CN0031', 4000),
    (11001, 'CN0301', 600),
    (11001, 'CN0291', 4200),
    (11001, 'CN3154', 1550),
    (11001, 'CN0291', 6000),
    (11001, 'CN3134', 2125),
    (11001, 'CN0031', 6000),
    (11002, '1N0271', 10000),
    (11002, '1N0264', 3700),
    (11002, '1N3192', 10280),
    (11002, '1N0267', 1925),
    (11002, '1N0264', 1500),
    (11002, '1N0265', 1910),
    (11002, '1N0282', 1625),
    (11002, '1N3244', 300),
    (11002, '1N3248', 1075),
    (11003, '2N3196', 2800),
    (11003, '2N3201', 950),
    (11003, '2N0271', 1690),
    (11003, '2N3197', 9975),
    (11003, '2N0243', 225),
    (11004, '3N3123', 16800),
    (11004, '3N3124', 3900),
    (11004, '3N3121', 19800),
    (11004, '3N3161', 7500),
    (11004, '3N3161', 5425),
    (11004, '3N3122', 4600),
    (11004, '3N3124', 6300),
    (11004, '3N3121', 1800),
    (11004, '3N3161', 10375),
    (11004, '3N3122', 12100),
    (11005, '4N3197', 2908),
    (11005, '4N3196', 250),
    (11005, '4N3194', 10000),
    (11005, '4N3195', 1950),
    (11005, '5N3021', 1025),
    (11005, '4N3192', 100),
    (11005, '4N3191', 5000),
    (11005, '4N3211', 1765),
    (11005, '5N0011', 2045),
    (11005, '4N3192', 4200),
    (11005, '4N3193', 5100),
    (11005, '4N3192', 700),
    (11006, '5N3291', 4850),
    (11006, '5N0181', 1325),
    (11006, '6N3011', 10327),
    (11006, '5N3243', 3900),
    (11006, '5N3302', 8800),
    (11006, '6N3021', 3850),
    (11006, '5N3243', 6075),
    (11006, '5N3302', 8895),
    (11006, '5N0171', 5225),
    (11006, '6N3031', 300),
    (11006, '6N3021', 1300)
;

105 rows affected

PMM	總訂單筆數	500 pc以下	501~1000pc(含)	1000 pc以上	前12個月
10905	5	3	0	2	0
10906	5	0	0	5	0
10907	5	0	0	5	5
10908	8	0	0	8	8
10909	10	1	1	8	10
10910	4	0	0	4	4
10911	6	0	3	3	6
10912	8	2	1	5	8
11001	7	0	1	6	7
11002	9	1	0	8	9
11003	5	1	1	3	5
11004	10	0	0	10	10
11005	12	2	1	9	12
11006	11	1	0	10	11

Warning: Null value is eliminated by an aggregate or other SET operation.