日期类型函数转换的特殊性
别的数据库,日期类型如果要必须得用函数转换,但是MySQL不需要,因为他会自动转换,只要书写是按照日期类型写的,不用日期函数转换。
desc select emp_no from salaries where emp_no =20247 and from_date='1985-03-01';
![](file:///D:/%E7%94%A8%E6%88%B7%E7%9B%AE%E5%BD%95/%E6%88%91%E7%9A%84%E6%96%87%E6%A1%A3/My%20Knowledge/temp/7e0a3a74-3a36-429d-b570-e6945f0e1c8e/128/index_files/dccbab1e-657a-474d-ac2c-891d24b436d4.png)
![](https://images2017.cnblogs.com/blog/520685/201709/520685-20170913235140360-1138284926.png)
使用日期函数转换
desc select emp_no from salaries where emp_no =20247 and from_date=str_to_date('1985-03-01','%Y-%m-%d');
![](https://images2017.cnblogs.com/blog/520685/201709/520685-20170913235156610-1792361550.png)
![](file:///D:/%E7%94%A8%E6%88%B7%E7%9B%AE%E5%BD%95/%E6%88%91%E7%9A%84%E6%96%87%E6%A1%A3/My%20Knowledge/temp/7e0a3a74-3a36-429d-b570-e6945f0e1c8e/128/index_files/9c039b31-6e6c-43cc-983a-2d72b946a523.png)