如何将varchar转换/转换为日期? [英] How to convert/cast varchar to date?

问题描述

我在mySQL 5.1中有一个日期列，其数据类型为varchar(mm-dd-yyyy).如何将其转换为DATE?

I have a date column with data type varchar(mm-dd-yyyy) in mySQL 5.1. How do I convert it to DATE?

这是我到目前为止所拥有的-

Here is what I have so far -

SELECT id, date 
FROM tableName 
WHERE (CAST((SUBSTRING (date FROM 7 FOR 4 )||'/'||SUBSTRING (date FROM 4 FOR 2 )||'/'||SUBSTRING (date FROM 1 FOR 2 )) AS DATE) >= '01/01/2012' ) 
ORDER BY date DESC;

获取此

错误-#1064-您的SQL语法有错误；查看手册 对应于您的MySQL服务器版本以获取正确的语法 在"FROM 7 FOR 4"附近使用

error - #1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'FROM 7 FOR 4 )

请帮助.

推荐答案

您可以使用MySQL的

You can use MySQL's STR_TO_DATE() function

SELECT id, date 
FROM tableName 
WHERE STR_TO_DATE(date,'%Y-%m-%d') >= '01/01/2012' 
ORDER BY date DESC;

尽管我怀疑您使用Unix时间戳会更轻松

Although I suspect you will have an easier time using Unix Timestamps

SELECT id, date 
FROM tableName 
WHERE UNIX_TIMESTAMP(STR_TO_DATE(date,'%d/%m/%Y')) >= UNIX_TIMESTAMP('01/01/2012') 
ORDER BY date DESC;

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