Look at the pic. How it even possible? How to avoid this?
I've no records with StartDate>='2013123-12-1'

Maximum year supported by MySQL is 9999.
MySQL retrieves and displays DATE values in 'YYYY-MM-DD' format. The supported range is '1000-01-01' to '9999-12-31'.
Source: http://dev.mysql.com/doc/refman/4.1/en/datetime.html :
1 warning, doshow warningsafter your query, you will see what it did