sql查询按两个字段查询重复记录

用关键字 stinct，select stinct 字段，是不重复的意思。代码的实例如下： 查询order_id和loan_lind两个字段相同的记录： select distinct a.order_preview_id, a.order_id, a.loan_kind from ddk_order_preview_info a join ddk_order_preview_info b on a.order_preview_id != b.order_preview_id where a.order_