mybatis-plus的查詢和條件構造器

通過id查詢

@Test
    void testQuery(){
        User user = userMapper.selectById(1L);
        System.out.println(user);
    }

通過id 批量查詢

@Test
    void testQuery(){
        List<User> users = userMapper.selectBatchIds(Arrays.asList(1L, 2L, 3L, 1272823863285137412L));
        users.forEach(System.out::println);
    }

User(id=1, name=Jone, age=18, email=修改時間成功否, createTime=Tue Jun 16 20:06:40 CST 2020, updateTime=Tue Jun 16 20:55:51 CST 2020)
User(id=2, name=Jack, age=20, email=test2@baomidou.com, createTime=null, updateTime=null)
User(id=3, name=Tom, age=28, email=test3@baomidou.com, createTime=null, updateTime=null)
User(id=1272823863285137412, name=修改時間成功否, age=3, email=123456789@qq.com, createTime=Tue Jun 16 20:58:57 CST 2020, updateTime=Tue Jun 16 21:04:31 CST 2020)

條件查詢

@Test
    void testQuery(){
        List<User> jack = userMapper.selectList(new LambdaQueryWrapper<User>().eq(User::getName, "Jack"));
        System.out.println(jack);
        //[User(id=2, name=Jack, age=20, [email protected], createTime=null, updateTime=null), User(id=6, name=Jack, age=3, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 22:05:12 CST 2020), User(id=7, name=Jack, age=3, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 22:05:12 CST 2020)]
    }

     @Test
    void testQuery(){
        Map<String,Object> map=new HashMap<>();
        map.put("name","jack");
        List<User> users = userMapper.selectByMap(map);
        users.forEach(System.out::println);
        //User(id=2, name=Jack, age=20, [email protected], createTime=null, updateTime=null)
        //User(id=6, name=Jack, age=3, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 22:05:12 CST 2020)
        //User(id=7, name=Jack, age=3, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 22:05:12 CST 2020)
    }

@Test
    void testQuery(){
        Map<String,Object> map=new HashMap<>();
        map.put("name","jack");
        map.put("age",3);
        List<User> users = userMapper.selectByMap(map);
        users.forEach(System.out::println);
        //User(id=6, name=Jack, age=3, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 22:05:12 CST 2020)
        //User(id=7, name=Jack, age=3, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 22:05:12 CST 2020)
    }

條件構造器

@Test
    void testQuery(){
    	List<User> users = userMapper.selectList(null);
        users.forEach(System.out::println);
        List<User> list1 = userMapper.selectList(new LambdaQueryWrapper<User>().eq(User::getName, "jack"));//eq :等於 =, 這個sql  where name='jack'
        list1.forEach(System.out::println);
        List<User> list2 = userMapper.selectList(new LambdaQueryWrapper<User>().eq(User::getName, "jack").eq(User::getAge,3));  //eq :等於 =, 這個sql  where name='jack' and age = 3
        list2.forEach(System.out::println);
        List<User> list3 = userMapper.selectList(new LambdaQueryWrapper<User>().ne(User::getName, "jack"));//ne :不等於 !=, 這個sql  where name!='jack'
        list3.forEach(System.out::println);
        List<User> list4 = userMapper.selectList(new LambdaQueryWrapper<User>().ne(User::getName, "jack").eq(User::getAge,18)); //ne :不等於 !=, 這個sql  where name!='jack' and age = 18
        list4.forEach(System.out::println);
        List<User> list5 = userMapper.selectList(new LambdaQueryWrapper<User>().gt(User::getAge,18));//gt :大於 >, 這個sql  where age>18    //ge >= ;   lt <    ;   le <=   ;
        list5.forEach(System.out::println);
        List<User> list6 = userMapper.selectList(new LambdaQueryWrapper<User>().between(User::getAge,10,20));//between :between and, 這個sql  where age between 10 and 20 //notBetween :NOT BETWEEN
        list6.forEach(System.out::println);
        List<User> list7 = userMapper.selectList(new LambdaQueryWrapper<User>().like(User::getName,"三"));//like :LIKE '%值%', 這個sql  where name like '%三%'   //notLike ：NOT LIKE '%值%'；likeLeft: LIKE '%值' ;likeRight:LIKE '值%'
        list7.forEach(System.out::println);
        List<User> list8 = userMapper.selectList(new LambdaQueryWrapper<User>().isNull(User::getCreateTime));//isNull:字段 IS NULL , 這個sql where create_time is null //isNotNull:字段 IS NOT NULL
        list8.forEach(System.out::println);


    }

全部數據

//eq    ne      gt      between     like    isNull
//User(id=1, name=Jone, age=18, email=修改時間成功否, createTime=Tue Jun 16 20:06:40 CST 2020, updateTime=Tue Jun 16 20:55:51 CST 2020)
//User(id=2, name=Jack, age=20, [email protected], createTime=null, updateTime=null)
//User(id=3, name=Tom, age=28, [email protected], createTime=null, updateTime=null)
//User(id=4, name=Sandy, age=21, [email protected], createTime=null, updateTime=null)
//User(id=5, name=Billie, age=24, [email protected], createTime=null, updateTime=null)
//User(id=6, name=Jack, age=3, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 22:05:12 CST 2020)
//User(id=7, name=Jack, age=3, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 22:05:12 CST 2020)
//User(id=1272823863285137410, name=張三, age=10, email=看修改時間, createTime=Tue Jun 16 20:06:40 CST 2020, updateTime=Tue Jun 16 20:06:40 CST 2020)
//User(id=1272823863285137411, name=李四, age=10, email=紅紅火火恍恍惚惚, createTime=null, updateTime=null)
//User(id=1272823863285137412, name=修改時間成功否, age=3, [email protected], createTime=Tue Jun 16 20:58:57 CST 2020, updateTime=Tue Jun 16 21:04:31 CST 2020)
//User(id=1272823863285137413, name=測試插入, age=18, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 22:05:12 CST 2020)
//User(id=1272823863285137414, name=李三, age=null, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 23:20:10 CST 2020)

//User(id=2, name=Jack, age=20, [email protected], createTime=null, updateTime=null)
//User(id=6, name=Jack, age=3, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 22:05:12 CST 2020)
//User(id=7, name=Jack, age=3, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 22:05:12 CST 2020)

//User(id=6, name=Jack, age=3, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 22:05:12 CST 2020)
//User(id=7, name=Jack, age=3, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 22:05:12 CST 2020)

//User(id=1, name=Jone, age=18, email=修改時間成功否, createTime=Tue Jun 16 20:06:40 CST 2020, updateTime=Tue Jun 16 20:55:51 CST 2020)
//User(id=3, name=Tom, age=28, [email protected], createTime=null, updateTime=null)
//User(id=4, name=Sandy, age=21, [email protected], createTime=null, updateTime=null)
//User(id=5, name=Billie, age=24, [email protected], createTime=null, updateTime=null)
//User(id=1272823863285137410, name=張三, age=10, email=看修改時間, createTime=Tue Jun 16 20:06:40 CST 2020, updateTime=Tue Jun 16 20:06:40 CST 2020)
//User(id=1272823863285137411, name=李四, age=10, email=紅紅火火恍恍惚惚, createTime=null, updateTime=null)
//User(id=1272823863285137412, name=修改時間成功否, age=3, [email protected], createTime=Tue Jun 16 20:58:57 CST 2020, updateTime=Tue Jun 16 21:04:31 CST 2020)
//User(id=1272823863285137413, name=測試插入, age=18, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 22:05:12 CST 2020)
//User(id=1272823863285137414, name=李三, age=null, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 23:20:10 CST 2020)

//User(id=1, name=Jone, age=18, email=修改時間成功否, createTime=Tue Jun 16 20:06:40 CST 2020, updateTime=Tue Jun 16 20:55:51 CST 2020)
//User(id=1272823863285137413, name=測試插入, age=18, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 22:05:12 CST 2020)

//User(id=2, name=Jack, age=20, [email protected], createTime=null, updateTime=null)
//User(id=3, name=Tom, age=28, [email protected], createTime=null, updateTime=null)
//User(id=4, name=Sandy, age=21, [email protected], createTime=null, updateTime=null)
//User(id=5, name=Billie, age=24, [email protected], createTime=null, updateTime=null)

//User(id=1, name=Jone, age=18, email=修改時間成功否, createTime=Tue Jun 16 20:06:40 CST 2020, updateTime=Tue Jun 16 20:55:51 CST 2020)
//User(id=2, name=Jack, age=20, [email protected], createTime=null, updateTime=null)
//User(id=1272823863285137410, name=張三, age=10, email=看修改時間, createTime=Tue Jun 16 20:06:40 CST 2020, updateTime=Tue Jun 16 20:06:40 CST 2020)
//User(id=1272823863285137411, name=李四, age=10, email=紅紅火火恍恍惚惚, createTime=null, updateTime=null)
//User(id=1272823863285137413, name=測試插入, age=18, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 22:05:12 CST 2020)

//User(id=1272823863285137410, name=張三, age=10, email=看修改時間, createTime=Tue Jun 16 20:06:40 CST 2020, updateTime=Tue Jun 16 20:06:40 CST 2020)
//User(id=1272823863285137414, name=李三, age=null, [email protected], createTime=Tue Jun 16 22:05:12 CST 2020, updateTime=Tue Jun 16 23:20:10 CST 2020)

//User(id=2, name=Jack, age=20, [email protected], createTime=null, updateTime=null)
//User(id=3, name=Tom, age=28, [email protected], createTime=null, updateTime=null)
//User(id=4, name=Sandy, age=21, [email protected], createTime=null, updateTime=null)
//User(id=5, name=Billie, age=24, [email protected], createTime=null, updateTime=null)
//User(id=1272823863285137411, name=李四, age=10, email=紅紅火火恍恍惚惚, createTime=null, updateTime=null)

 @Test
    void testQuery2(){
        List<Long> list=new ArrayList<>();
        list.add(1L);
        list.add(2L);
        list.add(1272823863285137412L);
        List<User> list1 = userMapper.selectList(new LambdaQueryWrapper<User>().in(User::getId, list));//in :in("id",{1,2,1272823863285137412})--->id in (1,2,1272823863285137412)
        list1.forEach(System.out::println);
        //User(id=1, name=Jone, age=18, email=修改時間成功否, createTime=Tue Jun 16 20:06:40 CST 2020, updateTime=Tue Jun 16 20:55:51 CST 2020)
        //User(id=2, name=Jack, age=20, [email protected], createTime=null, updateTime=null)
        //User(id=1272823863285137412, name=修改時間成功否, age=3, [email protected], createTime=Tue Jun 16 20:58:57 CST 2020, updateTime=Tue Jun 16 21:04:31 CST
        // 2020)
        List<User> list2 = userMapper.selectList(new LambdaQueryWrapper<User>().in(User::getId, 1L, 2L, 1272823863285137412L));//in :in("id", 1, 2,1272823863285137412)--->id in (1,2,1272823863285137412)
        list2.forEach(System.out::println);
        //User(id=1, name=Jone, age=18, email=修改時間成功否, createTime=Tue Jun 16 20:06:40 CST 2020, updateTime=Tue Jun 16 20:55:51 CST 2020)
        //User(id=2, name=Jack, age=20, [email protected], createTime=null, updateTime=null)
        //User(id=1272823863285137412, name=修改時間成功否, age=3, [email protected], createTime=Tue Jun 16 20:58:57 CST 2020, updateTime=Tue Jun 16 21:04:31 CST
        // 2020)
    }

@Test
    void testQuery3(){
        //groupBy
        List<User> list1 = userMapper.selectList(new LambdaQueryWrapper<User>().groupBy(User::getName));//GROUP BY name
        list1.forEach(System.out::println);
        List<User> list2 = userMapper.selectList(new LambdaQueryWrapper<User>().groupBy(User::getName,User::getAge));//GROUP BY (name,age)
        list2.forEach(System.out::println);
    }

@Test
    void testQuery4(){
        //orderByAsc    orderByDesc
        List<User> list1 = userMapper.selectList(new LambdaQueryWrapper<User>().orderByDesc(User::getAge));//ORDER BY 字段, ... DESC --->order by age DESC
        list1.forEach(System.out::println);
        List<User> list2 = userMapper.selectList(new LambdaQueryWrapper<User>().orderByDesc(User::getAge).orderByAsc(User::getId));//ORDER BY 字段, ... DESC --->order by age DESC id asc
        list2.forEach(System.out::println);
    }

@Test
    void  testQuery6(){
        //or
        List<User> users = userMapper.selectList(new LambdaQueryWrapper<User>().or().eq(User::getName, "jack").or().eq(User::getAge, "18"));//or------>後接方法，這裏sql  or name='jack' or age = 18
        users.forEach(System.out::println);
    }

mybatis-plus的查詢和條件構造器

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