mysql 給返回列表排序添加序號列

SELECT (@i:=@i+1) rankNum,userLeaderboard.userId,userLeaderboard.userName,userLeaderboard.totalAmount
	FROM (
			SELECT 
				s.user_id userId,u.USER_NAME userName,sum(s.pay_amount) totalAmount
				FROM t_sale_deal_info s,t_user u
				WHERE s.user_id=u.id AND s.pay_date_time>='2020-07-03 00:00:00' AND s.pay_date_time<='2020-07-07 23:59:59'
				GROUP BY s.user_id
			) userLeaderboard,
			(select @i:=0) as it
	ORDER BY userLeaderboard.totalAmount desc

:=   賦值的意思。在set update select 中表示賦值的意思，用的比較少一般都用=，但是在用變量實現行號時（比如本文標題獲取排列序號），一定要用:=。

 =   等於的意思，只有當set 和 update時，和:=的意思是一樣的，表示賦值，其餘情況都是等於的意思。

上面的sql主要在(@i:=@i+1) rankNum和 (select @i:=0) as it這兩點

 

注意如果是JPA hibernate注意:冒號，框架會識別爲參數的前綴，需要\\轉義,如:

@Override
    public List<Map<String, Object>> getAllAmountByUser(String startTime, String endTime) {
        String sql=" SELECT (@i\\:=@i+1) rankNum,userLeaderboard.userId,userLeaderboard.userName,userLeaderboard.totalAmount "+
                   "     FROM ( "+
                   "             SELECT "+
                   "             s.user_id userId,u.USER_NAME userName,sum(s.pay_amount) totalAmount "+
                   "             FROM t_sale_deal_info s,t_user u "+
                   "             WHERE s.user_id=u.id AND s.pay_date_time>=:startTime AND s.pay_date_time<=:endTime "+
                   "             GROUP BY s.user_id "+
                   "           ) userLeaderboard, "+
                   "           (select @i\\:=0) as it "+
                   "     ORDER BY userLeaderboard.totalAmount desc";

        Query query = em.createNativeQuery(sql);
        query.setParameter("startTime",startTime);
        query.setParameter("endTime",endTime);
        query.unwrap(SQLQuery.class).setResultTransformer(Transformers.ALIAS_TO_ENTITY_MAP);
        return query.getResultList();
    }