SQL 两列重复查询答:create table test([列表1] varchar(10),[列表2] varchar(10))insert into test select '1','A'union select '1','B'union select '2','A'union select '2',nullunion select '3','A'union select '3',NULLunion select '4','A'union select '4',NULLunion select '5',NULLunion...