您可以使用ROW_NUMBER解析函数和PARTITION BY主键中除c1之外的所有列，然后按DESC结束顺序使用ORDER BY c1，然后过滤仅返回每个分区中编号最早的行：

SELECT *
FROM   (
  SELECT t.*,
         ROW_NUMBER() OVER (
           PARTITION BY c2, c3, c4, c5 -- All the primary key columns except c1
           ORDER BY c1 DESC
         ) AS rn
  FROM   table_name t
)
WHERE  rn = 1;

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