- 通过id查询
@Test
void testQuery(){
User user = userMapper.selectById(1L);
System.out.println(user);
}
- 通过id 批量查询
@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=修改时间成功否, 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=修改时间成功否, age=3, email=123456789@qq.com, createTime=Tue Jun 16 20:58:57 CST 2020, updateTime=Tue Jun 16 21:04:31 CST 2020)
- 条件查询
@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)
}
- 条件构造器
@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 :等于 =, 这个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 :等于 =, 这个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 :不等于 !=, 这个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 :不等于 !=, 这个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 :大于 >, 这个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, 这个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%', 这个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 , 这个sql where create_time is null //isNotNull:字段 IS NOT NULL
list8.forEach(System.out::println);
}
全部数据
//eq ne gt between like isNull
//User(id=1, name=Jone, age=18, email=修改时间成功否, 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=张三, age=10, email=看修改时间, 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=红红火火恍恍惚惚, createTime=null, updateTime=null)
//User(id=1272823863285137412, name=修改时间成功否, 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=测试插入, 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=修改时间成功否, 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=张三, age=10, email=看修改时间, 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=红红火火恍恍惚惚, createTime=null, updateTime=null)
//User(id=1272823863285137412, name=修改时间成功否, 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=测试插入, 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=修改时间成功否, createTime=Tue Jun 16 20:06:40 CST 2020, updateTime=Tue Jun 16 20:55:51 CST 2020)
//User(id=1272823863285137413, name=测试插入, 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=修改时间成功否, 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=张三, age=10, email=看修改时间, 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=红红火火恍恍惚惚, createTime=null, updateTime=null)
//User(id=1272823863285137413, name=测试插入, 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=张三, age=10, email=看修改时间, 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=红红火火恍恍惚惚, 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=修改时间成功否, 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=修改时间成功否, 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=修改时间成功否, 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=修改时间成功否, 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------>后接方法,这里sql or name='jack' or age = 18
users.forEach(System.out::println);
}