如何将/ varchar转换为日期？

Question

我varchar(mm-dd-yyyy)在mySQL 5.1中有一个数据类型的日期列.如何将其转换为DATE？

这是我到目前为止 -

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;

得到这个

错误 - #1064 - 您的SQL语法出错; 查看与您的MySQL服务器版本对应的手册,以便在'FROM 7 FOR 4附近使用正确的语法

请帮忙.

Answer 1

你可以使用MySQL的STR_TO_DATE()功能

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

虽然我怀疑你会更容易使用Unix时间戳

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