SQL-Teradata：如何創建一個由公式組成的新列

Question

cust_id acct_id trxn_amt trxn_cnt 
1 66685638 10,028,717,398 199.75 5 
2 66685638 10,028,849,377 76.16 2 

假設我有一個包含多個帳戶ID的客戶表，並且我想創建一個新列以便爲所有交易金額的總和每個客戶（cust_id爲199.75 + 76.16 = 66685638），另一列爲每個賬戶總支出的百分比（對於第一個賬戶爲199.75 /（76.15 + 199.75））。每個客戶可能擁有2-4個acct_ids。

非常感謝。

Answer 1

怎麼樣：

select cust_id, 
     sum(trxn_amt) as total_amount, 
     trxn_amt/sum(trxn_amt) as pct 
from customers 
group by cust_id 
order by cust_id; 

，或者如果你想看到從客戶表中每個單排：

select cust_id, 
     acct_id, 
     trxn_amt, 
     sum(trxn_amt) as over (partition by cust_id) as total_amount, 
     trxn_amt/sum(trxn_amt) as over (partition by cust_id) as pct 
from customers 
order by cust_id;