列出客戶ID，名稱和所有他/她的帳戶

Question

customers: 
+------------+--------------+ 
| cid  | Name   | 
+------------+--------------+ 
| 1   | Bob   | 
| 2   | John   | 
| 3   | Jane   | 
+------------+--------------+ 
accounts: 
+------------+--------------+ 
| aid  | type   | 
+------------+--------------+ 
| 1   | Checking  | 
| 2   | Saving  | 
| 3   | CD   | 
+------------+--------------+ 
transactions: 
+------------+--------------+--------------+ 
| tid  | cid   | aid   | 
+------------+--------------+--------------+ 
| 1   | 1   | 1   | 
| 2   | 2   | 1   | 
| 3   | 1   | 2   | 
| 4   | 2   | 3   | 
| 5   | 3   | 1   | 
+------------+--------------+--------------+ 

我想寫一個plsql過程，給定客戶ID作爲參數，將顯示他/她的ID，名稱和所有帳戶。顯示id和名字很簡單。我不確定的是如何獲取所有與客戶ID關聯的帳戶以及如何檢索多個帳戶。

Answer 1

一個IDEEA可以是：

select c.cid, c.name, a.type 
from customers c 
left join transactions t on (t.cid = c.cid) 
left join accounts a on (a.aid = t.aid) 
where c.cid = :customer_id 
group by c.cid, c.name, a.type; 

由需要對組中，因爲可以更交易。

此外，如果你想看到一個行：

select cid, name, LISTAGG(type, ',') WITHIN GROUP (ORDER BY type) as account_types 
from(
    select distinct c.cid, c.name, a.type 
    from customers c 
    left join transactions t on (t.cid = c.cid) 
    left join accounts a on (a.aid = t.aid) 
    where c.cid = :customer_id 

) 
group by cid, name; 

把這個變成一個存儲過程/函數是太簡單了，所以我讓他給你。