PL/SQL - 數值或值錯誤

Question

Oracle給我的錯誤「ORA-06502：PL/SQL：數字或值錯誤：字符到數字轉換錯誤ORA-06512：在行15 06502. 00000 - 」PL/SQL：數字或值錯誤％的」

DECLARE 
idnumber NUMBER(10); 
initials VARCHAR2(100); 
userid VARCHAR2(100); 
old_initials VARCHAR2(100); 
CURSOR cursor1 IS 
SELECT s_first, s_last FROM tst_student ORDER BY s_first; 
student cursor1%ROWTYPE; 
BEGIN 
FOR student IN cursor1 LOOP 
idnumber :=1; 
old_initials := SUBSTR(student.s_first,1,1) || SUBSTR(student.s_last,1,1); 
initials := SUBSTR(student.s_first,1,1) || SUBSTR(student.s_last,1,1); 
IF initials = old_initials THEN 
userid := old_initials || '00' || idnumber + 1; 
ELSE idnumber := 1; 
END IF; 
DBMS_OUTPUT.PUT_LINE(userid); 
END LOOP; 
END; 

它抱怨該生產線是用戶ID：= old_initials || '00' ||的IDNumber + 1;

由於

Answer 1

變化即line to this：

userid := old_initials || '00' || (idnumber + 1); -- use brackets around the calculation 

問題是Oracle正在試圖級聯文本添加到數1，即甲骨文解析爲userid := (old_initials || '00' || idnumber) + 1

Answer 2

假設user_id是數字字段你原來的路線，使用to_number向數字作爲字符串轉換：

userid := to_number(old_initials || '00' || (idnumber + 1)); 

如果是varchar類型，

userid := old_initials || '00' || (idnumber + 1); 

編輯：要增加，對號碼：

idnumber := idnumber +1; 
    userid := to_number(old_initials || '00' ||idnumber); 

對於VARCHAR：

idnumber := idnumber +1; 
userid := old_initials || '00' || idnumber + 1; 

EDIT1：糾正的段：

idnumber :=1; 
    old_initials := ''; 
    FOR student IN cursor1 LOOP 
    initials := SUBSTR(student.s_first,1,1) || SUBSTR(student.s_last,1,1); 
    IF initials = old_initials THEN 
     idnumber := idnumber +1; 
     userid := old_initials || '00' || idnumber; 
    ELSE 
     idnumber := 1; 
     old_initials := initials; 
    END IF; 
    DBMS_OUTPUT.PUT_LINE(userid); 
    END LOOP; 
    END;