SQL - 删除除一组最大值之外的所有记录

Question

请帮忙SQL查询。我有一张桌子：

创建表 tblTest （ Id INT 主键不为空， 重量 INT NULL, 批处理 INT NULL， t_stamp 日期时间 null );

让我们假设它充满了值：

插入批量数据WillieNelson （ WT401_原始， 批处理完成信号， 批次号， t_stamp ） 值 (31, 3994, 2, '2023-12-05 06:19:58.990'), (32, 4052, 2, '2023-12-05 06:37:24.883'), (33, 4000, 5, '2023-12-05 08:44:09.780'), (34, 4058, 5, '2023-12-05 08:58:59.683'), (35, 4032, 8, '2023-12-05 11:18:11.727'), (36, 3983, 11, '2023-12-05 13:20:35.167'), (37, 4013, 11, '2023-12-05 13:33:54.877'), (38, 3993, 14, '2023-12-05 15:29:50.060'), (39, 3470, 14, '2023-12-05 15:48:51.053'), (40, 3996, 14, '2023-12-05 17:20:09.893'), (41, 3348, 14, '2023-12-05 17:39:22.477'), (42, 3993, 20, '2023-12-05 19:48:42.117'), (43, 4054, 20, '2023-12-05 20:09:12.217'), (44, 3991, 23, '2023-12-05 22:55:45.020'), (45, 4065, 23, '2023-12-05 23:16:12.077'), (46, 3993, 26, '2023-12-06 02:56:29.713'), (47, 4033, 26, '2023-12-06 03:12:24.483'), (48, 3982, 26, '2023-12-06 06:06:45.720'), (49, 4075, 26, '2023-12-06 06:35:05.197'), (50, 3994, 4, '2023-12-06 08:02:58.887'), (51, 3029, 4, '2023-12-06 08:28:21.260'), (52, 3982, 7, '2023-12-06 09:49:23.497'), (53, 4038, 7, '2023-12-06 10:12:41.707' )

我有一个表，其中有错误写入的额外记录。我需要删除它们。下面是桌子的图片。

我需要根据 Batch_Number 的分组来评估 Weight 列的最大值。相同的 Batch_Number 可以多次使用。因此，在没有对表进行排序的情况下，我试图查找 Batch_Number 中的更改并将这些行视为一个组来进行评估，而不必遍历每个记录

预期结果

身份证	重量	批量	t_邮票
32	4052	2	'2023-12-05 06:37:24.883'
34	4058	5	'2023-12-05 08:58:59.683'
35	4032	8	'2023-12-05 11:18:11.727'
37	4013	11	'2023-12-05 13:33:54.877'
40	3996	14	'2023-12-05 17:20:09.893'
43	4054	20	'2023-12-05 20:09:12.217'
49	4075	26	'2023-12-06 06:35:05.197'
50	3994	4	'2023-12-06 08:02:58.887'
53	4038	7	'2023-12-06 10:12:41.707'

Answer 1

WITH MaxWeightPerBatch AS (
    SELECT Batch_Number, MAX(Weight) AS MaxWeight
    FROM tblTest
    GROUP BY Batch_Number
)
DELETE FROM tblTest
WHERE (Batch_Number, Weight) NOT IN (
    SELECT Batch_Number, MaxWeight
    FROM MaxWeightPerBatch
);

找到每个 Batch_Number 组的最大权重，然后从 tblTest 中删除在各自的 Batch_Number 组内没有最大权重的行。