使用mysql查询将日期从'yyyy-dd-mm'转换为'yyyy-mm-dd'

Question

I am working on a database which has date fields in 'yyyy-dd-mm hh:mm' format, I used STR_TO_DATE to change the field to 'yyyy-mm-dd hh:mm' but it is giving back an error.

Query:

UPDATE transaction 
SET time_creation = STR_TO_DATE(time_creation, '%Y-%m-%d %H:%i');

Error:

Incorrect datetime value: '2005-08-06 15:57:00' for function str_to_date

I did a check with the following query too:

SELECT 
   time_creation, 
   STR_TO_DATE(time_creation,'%Y-%m-%d %H:%i') AS DATE_FORMATTED 
FROM transaction;

and got NULL in the DATE_FORMATTED column for date values such as '2007-22-11 15:32' but worked fine for '2007-09-11 13:12' . I don't understand what exactly is happening. Any help is appreciated.. thank you.

Answer 1

You have

STR_TO_DATE(time_creation,'%Y-%m-%d %H:%i')

and you give '2007-22-11 15:32' which means 'yyyy- dd -* mm * hh:mm'.

Sql is trying to parse a date that contains the number 22 as month...

Abyway

SELECT STR_TO_DATE('2005-08-06 15:57:00', '%Y-%m-%d %H:%i');

works fine in my mysql server.

Answer 2

First, you need to share the table definition with us. It sounds like the column type for the time_creation field is a VARCHAR and not a DATETIME. So you really should not try to store the result back into the same field. You want to save it into a valid DATETIME field so that the intrinsic column type is correct.

Second, it sounds like some of your values are stored as YYYY-DD-MM and some as YYYY-MM-DD. Is that the case? If it is, you'll need more logic in order to differentiate between the values that are already correct and those that are not. If they are mixed, however, you are in a bit of a pickle because how do you know the proper way to interpret 2012-01-03?

EDIT:

Create a new DATETIME field (for the example I just use new_time_creation) and update like this:

UPDATE transaction SET new_time_creation = STR_TO_DATE(time_creation, '%Y-%d-%m %H:%i');