从表中选择记录直到重复

Question

有没有一种方法可以从表中选择一组记录，按列排序，直到重复。

表名 --> 临时

列 --> key1, key2, key3, key4, rowCount

选择条件

1. 按行数排序
2. 直到 key1、key2 和 key3 的组合出现重复

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键1 | 关键2 | 键3 | 关键4 | 行数

k1.1 | k2.1 | k2.1 | k3.1 | k3.1 k4.1 | k4.1 1

k1.2 | k2.2 | k2.2 | k3.2 | k3.2 k4.2 | k4.2 2

k1.3 | k2.3 | k2.3 | k3.3 | k3.3 | k4.3 | k4.3 | 3

k1.1 | k2.1 | k2.1 | k3.1 | k3.1 k4.4 | k4.4 4

k1.5 | k2.5 | k2.5 k3.5 | k4.5 | k4.5 | 5

k1.6 | k2.6 | k2.6 k3.6 | k3.6 k4.6 | k4.6 6

选择查询应该返回以下记录

k1.1 | k2.1 | k2.1 | k3.1 | k3.1 k4.1 | k4.1 1

k1.2 | k2.2 | k2.2 | k3.2 | k3.2 | k4.2 | k4.2 2

k1.3 | k2.3 | k2.3 | k3.3 | k3.3 | k4.3 | k4.3 | 3

Answer 1

WITH 行编号为 AS ( 选择 *, ROW_NUMBER() OVER (PARTITION BY your_column ORDER BY your_sort_column) AS row_num 从 你的表 ） 选择 * FROM 行编号 其中 row_num = 1;