casting in MySQL

Question

I have a varchar field that looks like (sadly I have no control over the data):

Fri, 30 Oct 2009 06:30:00 EDT

Is there a way to cast this into a timestamp format so that I can then sort based on it?

Answer 1

Have you tried:

SELECT [...], CAST(varchar_field as DATETIME) as converted FROM [...]

See manual entry for cast here.

If that doesn't work, you can try the str_to_date function. This function takes a string and a format description and converts it to a date-value. These are the formatting values you can use:

%a  Abbreviated weekday name (Sun..Sat)
%b  Abbreviated month name (Jan..Dec)
%c  Month, numeric (0..12)
%D  Day of the month with English suffix (0th, 1st, 2nd, 3rd, …)
%d  Day of the month, numeric (00..31)
%e  Day of the month, numeric (0..31)
%f  Microseconds (000000..999999)
%H  Hour (00..23)
%h  Hour (01..12)
%I  Hour (01..12)
%i  Minutes, numeric (00..59)
%j  Day of year (001..366)
%k  Hour (0..23)
%l  Hour (1..12)
%M  Month name (January..December)
%m  Month, numeric (00..12)
%p  AM or PM
%r  Time, 12-hour (hh:mm:ss followed by AM or PM)
%S  Seconds (00..59)
%s  Seconds (00..59)
%T  Time, 24-hour (hh:mm:ss)
%U  Week (00..53), where Sunday is the first day of the week
%u  Week (00..53), where Monday is the first day of the week
%V  Week (01..53), where Sunday is the first day of the week; used with %X
%v  Week (01..53), where Monday is the first day of the week; used with %x
%W  Weekday name (Sunday..Saturday)
%w  Day of the week (0=Sunday..6=Saturday)
%X  Year for the week where Sunday is the first day of the week, numeric, four digits; used with %V
%x  Year for the week, where Monday is the first day of the week, numeric, four digits; used with %v
%Y  Year, numeric, four digits
%y  Year, numeric (two digits)
%%  A literal “%” character
%x  x, for any “x” not listed above

Answer 2

SELECT  STR_TO_DATE('Fri, 30 Oct 2009 06:30:00 EDT', '%a, %d %b %Y %H:%i:%s EDT')

Answer 3

Use STR_TO_DATE

But keep in mind that this is inefficient for a large number of rows.

mysql> SELECT  STR_TO_DATE("Fri, 30 Oct 2009 06:30:00 EDT", "%a, %e %b %Y %H:%i:%S EDT");
+---------------------------------------------------------------------------+
| STR_TO_DATE("Fri, 30 Oct 2009 06:30:00 EDT", "%a, %e %b %Y %H:%i:%S EDT") |
+---------------------------------------------------------------------------+
| 2009-10-30 06:30:00                                                       | 
+---------------------------------------------------------------------------+
1 row in set (0.03 sec)