我有两个我想加入的数据框：
第一个（产品）如下所示：
category,deleted,availability,approval,quality_issue,expiring,merchant_id,date,product_id
alimentation & boissons,-2.0,in stock,0,0.0,0.0,11061,08/30/2017,7997
alimentation & boissons,-2.0,in stock,approved,-2.0,0.0,11061,08/30/2017,65
alimentation & boissons,1.0,in stock,0,0.0,0.0,11061,08/30/2017,2186
然后我还有一个（帐户），如下所示：
merchant_id, status
11060, 0
11061, Not performing automatic item updates for availability
理想情况下，我最后想要的是一个数据框，其中包含所有值（在末尾添加状态作为列）：
category,deleted,availability,approval,quality_issue,expiring,merchant_id,date,product_id, status
alimentation & boissons,-2.0,in stock,0,0.0,0.0,11061,08/30/2017,7997, Not performing automatic item updates for availability
alimentation & boissons,-2.0,in stock,approved,-2.0,0.0,11061,08/30/2017,65, Not performing automatic item updates for availability
alimentation & boissons,1.0,in stock,0,0.0,0.0,11061,08/30/2017,2186, Not performing automatic item updates for availability
我正在使用这种合并类型：
merged = pd.merge(account_statuses_agg,
account_statuses_df,
left_on='merchant_id',
right_on='merchant_id',
how='outer'
).replace(np.nan, 0)
然而，我得到的结果是：
category,deleted,availability,approval,quality_issue,expiring,merchant_id,date,product_id, status
alimentation & boissons,-2.0,in stock,0,0.0,0.0,11061,08/30/2017,7997, 0
alimentation & boissons,-2.0,in stock,approved,-2.0,0.0,11061,08/30/2017,65, 0
alimentation & boissons,1.0,in stock,0,0.0,0.0,11061,08/30/2017,2186, 0
0 ,0 , 0 ,0 ,0 ,0 11061, 0 ,0 , Not performing automatic item updates for availability
合并正在发生的事情是什么？是否每个值都是唯一的，以便合并/加入pandas？
非常感谢！