Question

无论我选择哪个数字，该函数始终返回0

create or replace function FNC_PRICE_AVE_BUY(PRICE_AVE in number)
    return number
    is
    V_AVE number(6,2);
begin
    select NVL((avg(AMOUNT_PRICE_BUY)),0) into V_AVE from BUYER
    where AMOUNT_PRICE_BUY = PRICE_AVE;
    return V_AVE;
end FNC_PRICE_AVE_BUY;
/
set serveroutput on;
select FNC_PRICE_AVEC_BUY(31) as Average_price_321 from dual;

Answer 1

select AMOUNT_PRICE_BUY from BUYER where AMOUNT_PRICE_BUY = 31;

上面查询的值返回空值，这就是为什么每次都为零的原因

Answer 2

根据您问题下方的评论2，我认为这是您想要的逻辑：

创建一个返回买家平均价格的函数。

该参数应为买方ID。

返回值是该买家的平均价格。

create or replace function FNC_PRICE_AVE_BUY(BUYER_ID in number)
    return number
    is
    V_AVE number(6,2);
begin
    select NVL((avg(AMOUNT_PRICE_BUY)),0) into V_AVE from BUYER
    where ID = BUYER_ID;
    return V_AVE;
end FNC_PRICE_AVE_BUY;

pl / sql函数返回错误

2 个答案: