Mybatis循环操作

批量插入

insert into user(user_id,name) values (1,'test0'),(2,'test1');

insert into

user(

user_id,name

)

values

(#{item.userId},#{item.name})

批量删除

delete from user where user_id in(1,2);

delete from user

where

user_id in

#{item}

批量更新

①：循环更新，连接数据库N次，效率低

update user set name = 'test0' where user_id=1;update user set name = 'test1' where user_id =2;

update user

name=#{name}

where user_id = #{item.userId}

②：循环更新，连接数据库一次，效率较高（case when的两种写法）

写法一：

update user set name = case user_id when 1 then 'test0' when 2 then 'test1' else name end where user_id in(1,2)

update user set name=

when #{item.userId} then #{item.name}

where user_id in

#{item.user_id}

写法二：

update user set name = case when user_id = 1 then 'test0' when user_id = 2 then 'test1' else name end where user_id in(1,2)

update user

                 set name =

             

when user_id = #{item.userId} then #{item.name}

             where id in

                

                 #{item.userId}