【Mybatis-plus-join】 joinAnd() join添加条件

Metadata

title: 【Mybatis-plus-join】 joinAnd() join添加条件
date: 2023-01-22 19:23
tags:
  - 行动阶段/完成
  - 主题场景/组件
  - 笔记空间/KnowladgeSpace/ProgramSpace/ModuleSpace
  - 细化主题/Module/Mybatis-plus-join
categories:
  - Mybatis-plus-join
keywords:
  - Mybatis-plus-join
description: 【Mybatis-plus-join】 joinAnd() join添加条件

【Mybatis-plus-join】 joinAnd() join添加条件

需要注意啊，这个最后一个下标是指的第几个join，因为有时候会出现多个连接，附表连接主表，附表的附表连接附表这样子

/*
        相信有很多情况需要限制join的表的限制条件那么就需要 
    joinAnd(SFunction<T, Object> field, Object val, int index)
*/

JoinLambdaWrapper<Users> wrapper = new JoinLambdaWrapper<>(Users.class);
wrapper.leftJoin(UsersAge.class,UsersAge::getId,Users::getAgeId)
      .joinAnd(UsersAge::getId,1,0) // 需要注意啊，这个最后一个下标是指的第几个join，因为有时候会出现多个连接，附表连接主表，附表的附表连接附表这样子
      .eq(UserAge::getAgeName,"95")
      .selectAs((cb) -> {
      cb.add(UserAge::getAgeName,"user_age_name")
        .add(UserAge::getAgeDoc)
        .add("mp永远滴神","mpnb");
    }).end();
// 执行查询
usersService.joinList(wrapper,UsersVo.class);

// 执行SQL 
select 
  users.user_id,
    users.user_name,
    users_age.age_name as user_age_name,
    users_age.age_doc,
    'mp永远滴神' as mpnb
from users users
  left join users_age users_age on users_age.id = users.age_id and users_age.id = 1
where (
    users_age.age_name = '95'

1.3.4版本后写法

    Joins.of(Users.class)
                .masterLogicDelete(false)
                .pushLeftJoin(UsersVo::getUsersAge, UsersAge.class)
                            .joinAnd(0, w -> w.eq(UsersAge::getId, Users::getAgeId)
                                            .ne(UsersAge::getId, 10))
                .isNotNull(UsersAge::getId).end().joinList(UsersVo.class)
   

    SELECT 
    users.user_name,users.create_time,users.age_id,users.content_json,users.user_id, t1.age_doc as t1_ageDoc , t1.age_name as t1_ageName , t1.create_time as t1_createTime , t1.content_json_age as t1_contentJsonAge , t1.id as t1_id 
    FROM users as users 
    LEFT JOIN users_age as t1 ON t1.id = users.age_id and (t1.id = users.age_id AND t1.id <> 10) WHERE (t1.id IS NOT NULL)