How to convert a string to date?

[useruser888]

Hi:

I am confused with the date field. I have the following html code for a birthdate, and I want to same it to a date field in a table:
<td>Birth Date: <input type="text" name="birthdate" size="8" maxlength="8"> ex. 19910101</td
....
mysql_query("INSERT INTO studentname (birthdate) values ('$_POST[birthdate]')";

Now I got error saying:

Error: Incorrect date value: '20000212'

Please help to fix it. Should I do some conversion? How do I do it?

Thank you for your help.

[useruser888]

Re: How to convert a string to date?

Thank you, I fixed the problem.