mybtis实现以下代码:select a.student_name as '学生姓名',c.class_name as '优秀班级', a.student_score as '最高成绩' from student_info a, (select Class_id,max(student_score) as maxs from student_info group by Class_id) b, (select * from student_class where is_class='优') c where c.id=a.Class_id and b.Class_id=c.id and a.student_score=b.maxs;
时间: 2023-05-29 14:05:57 浏览: 55
由于无法确定表结构,以下SQL仅供参考:
SELECT a.student_name AS '学生姓名', c.class_name AS '优秀班级', a.student_score AS '最高成绩'
FROM student_info a
INNER JOIN (
SELECT Class_id, MAX(student_score) AS maxs
FROM student_info
GROUP BY Class_id
) b ON a.Class_id = b.Class_id AND a.student_score = b.maxs
INNER JOIN student_class c ON c.id = a.Class_id AND c.is_class = '优';
相关问题
请使用mybatis表示以下sql语句:SELECT s.id ,partner_id,r.name FROM `sale_order` as s left join res_partner as r on s.partner_id = r.id ;
使用MyBatis的注解方式表示以上SQL语句可以如下:
```java
@Select("SELECT s.id, partner_id, r.name FROM sale_order s LEFT JOIN res_partner r ON s.partner_id = r.id")
List<SaleOrderDTO> selectSaleOrderAndPartner();
```
其中,`SaleOrderDTO`为返回结果对象。如果使用XML方式配置SQL语句,则可以如下编写:
```xml
<select id="selectSaleOrderAndPartner" resultType="SaleOrderDTO">
SELECT s.id, partner_id, r.name FROM sale_order s LEFT JOIN res_partner r ON s.partner_id = r.id
</select>
```
select a.device_id, a.site_id, a.device_sn, b.site_name, a.door_state, c.address, c.lng, c.lat from device as a left join operate_site as b on a.operate_site_id = b.id left join operate_device_prod as c on a.id = c.device_id where a.device_sn in (#{snList}) 如果snList是一个集合,这个SQL正确吗?
如果`snList`是一个集合,您需要将SQL语句中的`in`子句进行相应的修改。在这种情况下,您可以使用`foreach`循环或者使用`JOIN`语句来构建一个临时表。
以下是两种不同的方法来处理这种情况:
1. 使用`foreach`循环:
如果您使用的是MyBatis或类似的框架,可以使用`foreach`循环来构建`in`子句。示例代码如下:
```sql
select
a.device_id,
a.site_id,
a.device_sn,
b.site_name,
a.door_state,
c.address,
c.lng,
c.lat
from device as a
left join operate_site as b
on a.operate_site_id = b.id
left join operate_device_prod as c
on a.id = c.device_id
where a.device_sn in
<foreach item="item" collection="snList" open="(" separator="," close=")">
#{item}
</foreach>
```
请注意,这里的`snList`是一个集合参数,您需要根据您的框架和语法进行适当的调整。
2. 使用临时表:
另一种方法是将`snList`作为一个临时表,然后将其与原始查询进行连接。示例代码如下:
```sql
with temp_sn_list(sn) as (
select unnest(ARRAY[#{snList}])
)
select
a.device_id,
a.site_id,
a.device_sn,
b.site_name,
a.door_state,
c.address,
c.lng,
c.lat
from device as a
left join operate_site as b
on a.operate_site_id = b.id
left join operate_device_prod as c
on a.id = c.device_id
where a.device_sn in (select sn from temp_sn_list);
```
请注意,这里使用了`unnest`函数将集合参数展开为一个临时表,然后使用子查询将其与原始查询进行连接。同样,您需要根据您的数据库和语法进行适当的调整。
请根据您的具体情况选择适合您的方法,并根据您使用的数据库和框架做相应的调整。