以下输出的Oracle SQL查询？

Question

Purchase Table

UserId    Date   Product
----------------------------
usr101    09-08-17  purchase
usr101    09-08-17  purchase
usr102    09-08-17  purchase
usr101    10-08-17  purchase
usr103    10-08-17  Purchase
usr103    10-08-17  Purchase
usr102    11-08-17  purchase
usr104    11-08-17  purchase

User Table

UserId    Name
-----------------
usr101   Fidal
usr102   robert
usr103   Lenin
usr104   Marx

我想要以下输出：

name   date        count(purchase)
fidal  09-08-17    2

1. 我要根据date计算购买数。
2. 我要根据userid计算购买数。

Answer 1

试试这个：

select u.Name,
       p.Date,
       count(1)
from purchase_table p
  JOIN user_table u
  ON p.UserId = u.UserId    
group by u.Name,
         p.Date

Answer 2

select 
     B.name, 
     A.date, 
     count(*)
from 
     purchaseTable A, 
     userTable B 
where 
     A.userId = B.userID 
group by 
     B.name, A.date