sql - Oracle 视图 ORA-00907: 缺少右括号

Question

SELECT 
    SALE.SaleID,
    SALE.SaleDate,
    CUSTOMER.CustomerID, 
    FIRSTNAMEFIRST(Customer.FirstName, Customer.LastName),
    SALE_ITEM.SaleItemID,
    SALE_ITEM.ItemID,
    ITEM.ItemDescription, 
    ITEM.ItemPrice
FROM CUSTOMER
INNER JOIN SALE ON CUSTOMER.CustomerID = SALE.CustomerID
INNER JOIN SALE_ITEM ON SALE.SaleID = SALE_ITEM.SaleID
INNER JOIN ITEM ON SALE_ITEM.ITEMID = ITEM.ItemID

即使当我测试视图时，它也会显示正确的查询结果，但我无法找出错误 ORA-00907。

函数定义

CREATE OR REPLACE FUNCTION FIRSTNAMEFIRST 
    ( FIRSTNAME IN VARCHAR2, LASTNAME IN VARCHAR2 ) RETURN VARCHAR2
AS 
BEGIN
    RETURN TRIM(FIRSTNAME) || ', ' || TRIM(LASTNAME);
END;

Answer 1

在我添加 AS FullName 之后它起作用了FIRSTNAMEFIRST(Customer.FirstName, Customer.LastName)。抱歉，如果我没有提供足够的信息，谢谢。