甲骨文：年份必須-4713和+9999之間，而不是0

Question

我有這樣

|---------------------------------| 
|EMPNO | HIREDATE | INDEX_NUM | 
|---------------------------------| 
|1  | 2012-11-13 | 1   | 
|2  | 2   | 1   | 
|3  | 2012-11-17 | 1   | 
|4  | 2012-11-21 | 1   | 
|5  | 2012-11-24 | 1   | 
|6  | 2013-11-27 | 1   | 
|7  | 2   | 2   | 
|---------------------------------| 

Oracle表我想對這個表

SELECT hiredate 
    FROM admin_emp 
    WHERE TO_DATE('hiredate','yyyy-mm-dd') >= TO_DATE('2012-05-12','yyyy-mm-dd'); 

執行此query但得到錯誤

ORA-01841: (full) year must be between -4713 and +9999, and not be 0 

任何想法..？這裏有什麼問題？

查詢的基礎：在SQL分別表示字符串文字

CREATE TABLE admin_emp (
     empno  NUMBER(5) PRIMARY KEY, 
     hiredate VARCHAR(255), 
     index_num NUMBER(5)); 


insert into admin_emp(empno,hiredate,index_num) values 
(1,'2012-11-13',1); 
insert into admin_emp(empno,hiredate,index_num) values 
(2,'2',1); 
insert into admin_emp(empno,hiredate,index_num) values 
(3,'2012-11-17',1); 
insert into admin_emp(empno,hiredate,index_num) values 
(4,'2012-11-21',1); 
insert into admin_emp(empno,hiredate,index_num) values 
(5,'2012-11-24',1); 
insert into admin_emp(empno,hiredate,index_num) values 
(6,'2013-11-27',1); 
insert into admin_emp(empno,hiredate,index_num) values 
(7,'2',2); 

Answer 1

單引號（'）。因此'hiredate'不是hiredate列，它只是一個varchar，當然，它不適合您指定的日期格式。剛落引號，你應該罰款：

SELECT hiredate 
FROM admin_emp 
WHERE TO_DATE(hiredate,'yyyy-mm-dd') >= -- No quotes 
     TO_DATE('2012-05-12','yyyy-mm-dd');