spring boot MybatisPlus 条件构造器

例：

  需求: 查询性别为(=)女 and 年龄大于100岁
  条件构造器: 动态拼接where条件的. 多条件中默认的链接符and
  常见逻辑运算符
  1.eq =   2.gt >   3.lt  <
   ge >= ,le  <=

 QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.eq("sex", "女")
                     .gt("age",100);
        List<User> userList = userMapper.selectList(queryWrapper);

like:

     需求: 1.查询名称中包含'精'字的男性  "%精%"
          2.查询以精结尾的              %精
          3.查询以精开头                精%
   
    @Test
    public void select04(){

        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.likeLeft("name", "精")
       // queryWrapper.like("name", "精")
                    .eq("sex", "男");
        List<User> userList = userMapper.selectList(queryWrapper);
        System.out.println(userList);
    }

排序

 
      需求: 查询sex=女,之后按照age 倒叙排列.如果年龄相同按照id降序排列.
    
    @Test
    public void select05(){
        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.eq("sex", "女")
                    .orderByDesc("age","id");
        List<User> userList = userMapper.selectList(queryWrapper);
        System.out.println(userList);
    }

in -》selectBatchIds

     需求: 查询id为 1,3,5,7,8,9的数据???
     关键字  in  or
     在关联查询中慎用
   
    @Test
    public void select06(){
        Integer[] ids = {1,3,5,7};
       /* List<Integer> idList = new ArrayList<>();
        idList.add(1);
        idList.add(3);
        idList.add(5);
        idList.add(7);
        idList.add(8);*/
        List<Integer> idList = Arrays.asList(ids);//数组转集合
        List<User> userList = userMapper.selectBatchIds(idList);
        System.out.println(userList);
    }