Incorrect datetime value for str_to_date I'm trying to copy a varchar column which contains dates in the format YYYY-MM-DD to a date column using str_to_date. 

My query is: 

UPDATE `subscribers` SET `srtdt` = STR_TO_DATE(`StartDate`, '%Y%m%d%');


I am getting error 1411: Incorrect datetime value: '2001-09-16'... This seems to be happening on the first row.

I have searched a lot for this but cannot find why this is happening - all other answers point towards the string being in the wrong format etc, and that doesn't seem to be the case with my problem.
Try it:

UPDATE subscribers SET srtdt = STR_TO_DATE(StartDate, '%Y-%m-%d');