MyBatis-Plus_查询进阶03

查询专栏：MP默认查询原则
查询的是数据库列名非实体类属性。

一、需求思路分析：

 5. 名字为王姓并且(年龄小于40或者邮箱不为空)
  sql：name like '王%' and (age < 40 or email is not null)

 6. 名字为王姓或者(年龄小于40并且年龄大于20并且邮箱不为空)
sql：name like '王%' or (age < 40 and age >20 and email is not null)

二、需求实战

5. 需求实战05

/**
     * 5. 名字为王姓并且(年龄小于40或者邮箱不为空)
     * sql：name like '王%' and (age < 40 or email is not null)
     */
    @Test
    public void selectByWrapper5() {
        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.likeRight("name", "王")
                    .and(wq -> wq.lt("age", 40)
                                 .or()
                                 .isNotNull("email"));

        List<User> userList = userMapper.selectList(queryWrapper);
        userList.forEach(System.out::println);
    }
    /*
       sql形式: SELECT id,name,age,email,manager_id,create_time FROM user WHERE name LIKE ? AND ( age < ? OR email IS NOT NULL )
     */

6. 需求实战06

    /**
     * 6. 名字为王姓或者(年龄小于40并且年龄大于20并且邮箱不为空)
     * sql：name like '王%' or (age < 40 and age >20 and email is not null)
     */
    @Test
    public void selectByWrapper6() {
        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.likeRight("name", "王")
                    .or(wq -> wq.lt("age", 40)
                                .gt("age", 20)
                                .isNotNull("email"));

        List<User> userList = userMapper.selectList(queryWrapper);
        userList.forEach(System.out::println);
    }
    /*
       sql形式: SELECT id,name,age,email,manager_id,create_time FROM user
       WHERE name LIKE ? OR ( age < ? AND age > ? AND email IS NOT NULL )
     */

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