SQL Server选择互异

听起来你想要“每组最多”。

一种方法是使用窗口功能 ROW_NUMBER 要对每组中的行进行编号,然后仅选择行号为1的行:

SELECT ColA, ColB, ColC, ColD
FROM
(
    SELECT
         ColA, ColB, ColC, ColD,
         ROW_NUMBER(PARTITION BY ColB, ColC ORDER BY ColD) AS rn
    FROM table1
) T1
WHERE rn = 1