Question

I thought I ran into a bug with MySQL 5.1, but the bug was in the perl code that’s creating the timestamps. perl’s localtime uses 0-11 for months, but MySQL’s datetime uses 1-12. So, I’ve got all these malformed timestamps that I need to update.

2012-00-19 09:03:30

This should be:

2012-01-19 09:03:30

The problem is that the date functions for MySQL return NULL on a 00 month. Is there a way to do this in MySQL?

EDIT: Solution =

 UPDATE test_stats 
 SET start_time = CAST(CONCAT(SUBSTRING(start_time, 1, 5), 
                       CAST((CAST(SUBSTRING(start_time, 6, 2) AS UNSIGNED) + 1) AS CHAR(2)),
                       SUBSTRING(start_time, 8, 12)) AS DATETIME);

By the way, I was using MySQL 5.1

Answer 1

This should work:

UPDATE MyTable
SET DateTimeField = 
    CAST (
     SUBSTRING(DateTimeString, 1, 5) -- '2012-'
   + CAST((CAST(SUBSTRING(DateTimeString, 6, 2) AS INT) + 1) AS VARCHAR) -- '00' => '1'
   + SUBSTRING(DateTimeString, 8, 12) -- '-19 09:03:30'
   AS DATETIME)

Test with this select

DECLARE @x VARCHAR(50) = '2012-00-19 09:03:30'

SELECT CAST(SUBSTRING(@x, 1, 5) 
     + CAST((CAST(SUBSTRING(@x, 6, 2) AS INT) + 1) AS VARCHAR) 
     + SUBSTRING(@x, 8, 12) AS DATETIME)