在Oracle 10g上創建聚合函數返回無用的錯誤

Question

我得到了一些幫助，並且被帶到this page和this explanation，它應該包含聚合事物的有效方法。

它建議使用de COLLECT函數和其他一些自定義的東西。我想與它相處，但錯誤消息（加上我的新手）並不是最有用的。

功能：

CREATE OR REPLACE TYPE t_varchar2_tab AS TABLE OF VARCHAR2(4000); 

CREATE OR REPLACE FUNCTION tab_to_string (
    p_varchar2_tab IN t_varchar2_tab, 
    p_delimiter  IN VARCHAR2 DEFAULT ',') 
RETURN VARCHAR2 IS 
    l_string  VARCHAR2(32767); 
BEGIN 
    FOR i IN p_varchar2_tab.FIRST .. p_varchar2_tab.LAST LOOP 
    IF i != p_varchar2_tab.FIRST THEN 
     l_string := l_string || p_delimiter; 
    END IF; 
    l_string := l_string || p_varchar2_tab(i); 
    END LOOP; 
    RETURN l_string; 
END tab_to_string; 

而且我的測試：

with my_table as 
(
    select 'user1' as usrid, 'ab' as prodcode from dual union 
    select 'user1' as usrid, 'bb' as prodcode from dual union 
    select 'user1' as usrid, 'a' as prodcode from dual union 
    select 'user2' as usrid, 'db' as prodcode from dual union 
    select 'user2' as usrid, 'b' as prodcode from dual union 
    select 'user2' as usrid, 'bfdd' as prodcode from dual 
) 
select 
    usrid, 
    tab_to_string(CAST(COLLECT(prodcode) AS t_varchar2_tab)) AS codes 
from 
    my_table 
group by 
    usrid 

能給我一個ORA-06553: PLS-306: wrong number or types of arguments in call to 'TAB_TO_STRING'

這是非常複製和過去從我在註明出處開始，這個功能對我來說很有意義..我錯過了什麼？

謝謝！

[編輯]科多已計算過的問題之一是甲骨文理解'a'作爲炭，而不是VARCHAR。這使問題成爲現實問題。我更新了它，所以它是專注。

Answer 1

由於我不太明白的原因，Oracle認爲合成表的PRODCODE列不是VARCHAR2列。如果你稍微修改PRODCODE值中的一個，它會工作：

with my_table as 
(
    select 'user1' as usrid, 'ab' as prodcode from dual union 
    select 'user1' as usrid, 'b' as prodcode from dual union 
    select 'user1' as usrid, 'c' as prodcode from dual union 
    select 'user2' as usrid, 'd' as prodcode from dual union 
    select 'user2' as usrid, 'e' as prodcode from dual union 
    select 'user2' as usrid, 'f' as prodcode from dual 
) 
select 
    usrid, 
    tab_to_string(CAST(COLLECT(prodcode) AS t_varchar2_tab)) AS codes 
from 
    my_table 
group by 
    usrid