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HomeDatabaseMysql TutorialMySQL字符串类型转换时间类型_MySQL

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如果MySQL数据库里面的某个时间用的是varchar(或者是char)类型的,这样可以方便系统使用而不用随便转换时间类型来适应数据库版本的不同,当要把取出的字段转换成时间类型的时候,可以按如下方法操作:

(1)str_to_date

这个函数可以把字符串时间完全的翻译过来

SQL语句可以这样写:

    SELECT str_to_date(`tablename`.`eventTime`,'%Y-%m-%d %H:%i:%s') from tablename

数据库中eventTime的类型是VARCHAR(20),这样就可以将类型抓换成时间类型。

(2)to_days

就像它的名字一样,它只能转换到每一天,就是说一天的时间字符串会被转换成一个数

 

转:

字符串类型转成时间类型,字符串值必须满足2010-10-19 17:08:00模式。

SELECT STR_TO_DATE('04/31/2004,13:2:26', '%m/%d/%Y,%H:%i:%s');成功。

注意,模式区分大小写。
SELECT STR_TO_DATE('2010 - 10 - 19, 17 : 08', '%Y - %m - %d, %H : %i');不成功。
SELECT STR_TO_DATE('2010-10-19,17:08', '%Y-%m-%d,%H:%i');去除所有空格后成功。
SELECT STR_TO_DATE(replace(createTime,' ',''), '%Y-%m-%d,%H:%i') from upload;预先显示转换结果。符合预期。
正式转换如下:
update upload set createTime=STR_TO_DATE(replace(createTime,' ',''), '%Y-%m-%d,%H:%i');
update uzer set createTime=STR_TO_DATE(replace(createTime,' ',''), '%Y-%m-%d,%H:%i');
update hlog set createTime=STR_TO_DATE(replace(createTime,' ',''), '%Y-%m-%d,%H:%i');
再将列定义转为datetime类型。
另外要注意,mysql只精确到秒而已

注:
%W 星期名字(Sunday……Saturday) 
%D 有英语前缀的月份的日期(1st, 2nd, 3rd, 等等。) 
%Y 年, 数字, 4 位 
%y 年, 数字, 2 位 
%a 缩写的星期名字(Sun……Sat) 
%d 月份中的天数, 数字(00……31) 
%e 月份中的天数, 数字(0……31) 
%m 月, 数字(01……12) 
%c 月, 数字(1……12) 
%b 缩写的月份名字(Jan……Dec) 
%j 一年中的天数(001……366) 
%H 小时(00……23) 
%k 小时(0……23) 
%h 小时(01……12) 
%I 小时(01……12) 
%l 小时(1……12) 
%i 分钟, 数字(00……59) 
%r 时间,12 小时(hh:mm:ss [AP]M) 
%T 时间,24 小时(hh:mm:ss) 
%S 秒(00……59) 
%s 秒(00……59) 
%p AM或PM 
%w 一个星期中的天数(0=Sunday ……6=Saturday ) 
%U 星期(0……52), 这里星期天是星期的第一天 
%u 星期(0……52), 这里星期一是星期的第一天 
%% 一个文字“%”。

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