SQL 逻辑:
- 首先找出所有重复的sku_id
- 在找出这些sku_id中关联的主键id最大的一条记录(用来保留,不删除)
- 两个sql合并 就可以筛选出来最终需要删除的id
select id from sku_and_goods_sign
where sku_id in (select sku_id from sku_and_goods_sign
group by sku_id having count(1) > 1) and id not in (select max(id) from sku_and_goods_sign
group by sku_id having count(1) > 1)