How to set to NULL a datetime with 0000-00-00 00:00:00 value?

Question

I need to change a few values on my DB.

I forgot to set nullable to the table and it set to 0000-00-00 00:00:00 by default.

Now I need to convert that value in <

Answer 1

You need to first make the column nullable:

ALTER TABLE mytable MODIFY COLUMN field DATETIME NULL;

And then update the values:

UPDATE mytable SET field = NULL WHERE field = '0000-00-00 00:00:00';

Answer 2

Unfortunately this will not work.
for:

update episodes set `ending` = NULL 
WHERE `ending` = '0000-00-00'

If 0000-00-00 is in the where clause, you get the error:

"1292 - Incorrect datetime value: '0000-00-00' for column 'ending' at row 1".

even if ending has NULL and defalut=null in field definition.

Answer 3

You need to first make the column nullable:

@Mysql5.7

Wrong :

update episodes set `ending` = NULL WHERE `ending` = '0000-00-00'

Correct :

update episodes set `ending` = NULL WHERE `ending` = 0000-00-00

Note: Remove the quote from the date value in your where clause. Hope it help someone

Answer 4

What worked for me is:

1. Set the field from datetime to varchar(191).
2. Update all rows with field = '0000-00-00 00:00:00' to NULL.
3. Set the field back to datetime.

Answer 5

From MySQL 5.7, SQL mode NO_ZERO_DATE makes this update impossible unless you firstly disable this restriction (for the duration of the transaction only).

SET sql_mode=(SELECT REPLACE(@@sql_mode,"NO_ZERO_DATE", ""));
UPDATE mytable SET field = NULL WHERE field = '0000-00-00 00:00:00';