1. To convert a VARCHAR containing a date to a DATETIME, use
STR_TO_DATE[
^].
SELECT STR_TO_DATE(LicExp, '%d/%m%Y') FROM foo;
SELECT STR_TO_DATE(LicExp, '%Y-%b-%d') FROM foo;
If you don't know which is the day, month, or year e.g. 12/12/12 then you're out of luck.
Parsing strings is messy, so if you ever have to store a date as a string,
use an international standard[
^], not an arbitrary format of your choice like the person who created your dataset did.