?
Solved

varchar to datetime mysql

Posted on 2011-09-20
7
Medium Priority
?
752 Views
Last Modified: 2012-05-12
hi,

i have huge db in which unknowingly i kept the column as varchar which actually has to be datetime. The data stored in it is in '16/September/2011' format.
Now i want to convert the data type to datetime without losing the data.
ie 2011-09-11 rest part can be ignored
is it possible?

db : mysql
programing language : php
0
Comment
Question by:Insoftservice
  • 4
  • 2
7 Comments
 
LVL 24

Expert Comment

by:johanntagle
ID: 36566984
http://dev.mysql.com/doc/refman/5.1/en/date-and-time-functions.html#function_str-to-date

in your case it should be STR_TO_DATE('16/September/2011','%d/%M/%Y')

0
 
LVL 13

Expert Comment

by:Hugh McCurdy
ID: 36566992
Here's what I'd do.

1. Insert a new column.
2. Modify any software you have that uses the old field and change it to use the new field.  Hopefully you'll find everything.
3. Write a PHP program to read from the old column and write to the new column.  
3a. If the new column has data, I wouldn't overwrite it unless you are interested in the most recent date in which case, I'd overwrite it if not the most recent.  Why?  In case you don't find all instances that use the old field in step #2.

4. If you are absolutely certain that you don't have any software remaining that uses the old column (and you are absolutely certain you'll never need to revert to a prior version) then you can delete the old column.  Me, I'd keep the old column around for quite some time.
0
 
LVL 24

Accepted Solution

by:
johanntagle earned 2000 total points
ID: 36566998
To complete the procedure:

1.  create a new date column
2.  run: update table_name set date_column= STR_TO_DATE(original_column,'%d/%M/%Y');
3.  drop the old column
0
Prepare for your VMware VCP6-DCV exam.

Josh Coen and Jason Langer have prepared the latest edition of VCP study guide. Both authors have been working in the IT field for more than a decade, and both hold VMware certifications. This 163-page guide covers all 10 of the exam blueprint sections.

 
LVL 24

Expert Comment

by:johanntagle
ID: 36567014
Agree with hmccurdy's steps, except you don't need a PHP program for step 3.  To not overwrite on existing data, just do:

update table_name set date_column= STR_TO_DATE(original_column,'%d/%M/%Y') where data_column IS NULL;
0
 
LVL 24

Expert Comment

by:johanntagle
ID: 36567047
data_column --> date_column
0
 
LVL 13

Expert Comment

by:Hugh McCurdy
ID: 36567061
johan, you are correct.  I just like writing PHP programs.  
0
 
LVL 15

Author Closing Comment

by:Insoftservice
ID: 36567413
hi,

i had that code but with different format and thats the reason why it was not working i did not dropped so as to be in safe hand.
Thanx it worked
0

Featured Post

Vote for the Most Valuable Expert

It’s time to recognize experts that go above and beyond with helpful solutions and engagement on site. Choose from the top experts in the Hall of Fame or on the right rail of your favorite topic page. Look for the blue “Nominate” button on their profile to vote.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article discusses how to implement server side field validation and display customized error messages to the client.
In this article, I’ll talk about multi-threaded slave statistics printed in MySQL error log file.
The viewer will learn how to create a basic form using some HTML5 and PHP for later processing. Set up your basic HTML file. Open your form tag and set the method and action attributes.: (CODE) Set up your first few inputs one for the name and …
In this video, Percona Solution Engineer Dimitri Vanoverbeke discusses why you want to use at least three nodes in a database cluster. To discuss how Percona Consulting can help with your design and architecture needs for your database and infras…
Suggested Courses
Course of the Month14 days, 20 hours left to enroll

840 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question