Oracle查询表中字段里数据是否有重复的方法

1、查找单个字段

select 字段名,count(*) from table group by 字段名 having count(*) > 1

2、查找组合字段：

select test_name1,test_name2,count(*) from table group by test_name1,test_name2 having count(*) > 1