zoukankan      html  css  js  c++  java
  • Mysql 使用sql删除同表中重复数据并加唯一索引

    同一张表中,假设以两个字段做唯一业务,这两个字段分别为key1,key2,

    则以这两个字段为唯一

    DELETE tablename FROM
        tablename ,
        (
            SELECT
                min(id) id,
               key1, key2
            FROM
                tablename 
            GROUP BY
                
                key1, key2
            HAVING
                count(*) > 1
        ) t2
    		WHERE
     tablename .key1=t2.key1 
    AND tablename .key2=t2.key2
    AND tablename .id > t2.id;
    

     增加唯一索引

    ALTER TABLE t_procurement_order_instock add unique index uniq_t_procurement_order_instock(`t_procurement_order_instock_id`);  

    ALTER TABLE tablename DROP INDEX ix_instock_date_warehouse_g_f_lu_standard_item, ADD INDEX idx_f_lu_standard_item_warehouse_g_item_status_instock_date(`f_lu_standard_item`,`warehouse_g`,`item_status`,`instock_date`);
    ALTER TABLE tablename DROP INDEX IND_PAY_ORDER_1;                                                                     ALTER IGNORE TABLE PAY_ORDER ADD UNIQUE INDEX IND_PAY_ORDER_1(ORDER_ID);               将ORDER_ID设为唯一索引(IND_PAY_ORDER_1)删除重复数据

      

  • 相关阅读:
    BFS(广搜训练题目)
    练习赛1(补题)
    练习赛1(AC题)
    codeup 1743: 算法3-4:表达式求值
    数学相关(更新ing)
    c语言常用函数(更新ing)
    大牛的博客(学习不止,更新不止)
    51nod 1005 大数加法
    js1-----预览js内容
    css10---转载---定位,浮动
  • 原文地址:https://www.cnblogs.com/stevenlii/p/11671005.html
Copyright © 2011-2022 走看看