Question

我正在运行此查询来测试我的功能

select first_name, last_name,get_balance_due(orders.order_id) 
from customers, orders, order_lines 
Where customers.customer_id=orders.customer_id and orders.order_id = order_lines.order_id and
 order_date >= to_date( '30-Nov-1999', 'DD-Mon-YYYY' )
   AND order_date<  to_date( '01-Dec-1999', 'DD-Mon-YYYY' );
Group By First_name, Last_name, get_balance_due(orders.order_id)

输出重复3次。

FIRST_NAME  LAST_NAME  GET_BALANCE_DUE(ORDERS.ORDER_ID)  
Jan  Busse  602450.56  
Jan  Busse  602450.56  
Jan  Busse  602450.56

函数get_balance_due

CREATE OR REPLACE FUNCTION Get_balance_due
(order_id_f NUMBER)
RETURN NUMBER
AS 
balance_due_f NUMBER;
BEGIN
SELECT SUM(total_amount) INTO balance_due_f
FROM order_lines
WHERE order_id_f = order_id
RETURN balance_due_f;
end;

我怎样才能得到1个结果而不是3？

Answer 1

从select语句中删除order_lines：

select first_name, last_name,get_balance_due(orders.order_id) 
from customers INNER JOIN orders
ON customers.customer_id=orders.customer_id
Where  
 order_date >= to_date( '30-Nov-1999', 'DD-Mon-YYYY' )
   AND order_date<  to_date( '01-Dec-1999', 'DD-Mon-YYYY' );

（并使用INNER JOINs）

消除多输出Oracle PL / SQL

1 个答案: