1 -- 查询重复的数据
2 SELECT * FROM yy_visit_plan 
　　　　WHERE 
　　(post_code,cust_tree_node_id,visit_year,visit_month,staff_type) IN 
　　　　(SELECT post_code,cust_tree_node_id,visit_year,visit_month,staff_type FROM yy_visit_plan 
　　　　GROUP BY post_code,cust_tree_node_id,visit_year,visit_month,staff_type HAVING COUNT(cust_tree_node_id) > 1);
3 
4 -- 删除重复数据
5 DELETE FROM yy_visit_plan 
　　WHERE 
　　(post_code,cust_tree_node_id,visit_year,visit_month,staff_type) IN 
　　(select * from
　　　　(SELECT post_code,cust_tree_node_id,visit_year,visit_month,staff_type FROM yy_visit_plan 
　　　　GROUP BY post_code,cust_tree_node_id,visit_year,visit_month,staff_type HAVING COUNT(cust_tree_node_id) > 1)
　　 a) 
　　AND 
　　plan_id NOT IN 
　　(select * from
　　　　(SELECT MAX(plan_id) as plan_id FROM yy_visit_plan GROUP BY post_code,cust_tree_node_id,visit_year,visit_month,staff_type HAVING COUNT(*)>1) 
　　b);