删除数据库中重复的数据

delete from t_info_class_relationship a

/* 查询所有的俩个外键重复的外键id  */
where (a.info_id,a.class_id) in (select info_id,class_id from t_info_class_relationship group by info_id,class_id having count(*) > 1)

/* 除去第一条记录  */
and rowid not in (select min(rowid) from t_info_class_relationship group by info_id,class_id having count(*)>1)