casting MySQL

Question

J'ai un champ varchar qui ressemble (malheureusement je n'ai aucun contrôle sur les données):

Fri, 30 Oct 2009 06:30:00 EDT 

est-il un moyen de lancer ce dans un format d'horodatage pour que je puisse puis trier en fonction dessus?

Answer 1

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

Answer 2

Avez-vous essayé:

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

Voir manual entry for cast here.

Si cela ne fonctionne pas, vous pouvez essayer le str_to_date function. Cette fonction prend une chaîne et une description de format et la convertit en une valeur-date. Ce sont les valeurs de mise en forme, vous pouvez utiliser:

 
%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 3

Utilisez STR_TO_DATE

Mais gardez à l'esprit que cela est inefficace pour un grand nombre de lignes.

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)