MySQL实现排行榜功能

实体类

@Data
public class User {

    /**
     * 排名
     */
    private Integer rowNum;

    /**
     * 用户姓名
     */
    private String username;

   /**
     * 成绩
     */
    private Double socre;   
   
}

SQL

select (@r :=@r + 1) as rowNum,username,score
  from db_score s,(select @r := 0) r
order by score desc

@r是MySQL中定义一个变量
@r := @r+1 将r+1的值赋值给变量r
(select @r := 0) r声明变量从0开始