I use KNIME 2.9.2 (but this problem occured at least one year ago) and mysql-connector-java-5.1.29 with a MySQL 5.1 databse.
Columns with a Date or DateTime type in the MySQL database I read with the database reader in KNIME return a date with the day before: In the table is '2014-04-23' and in KNIME I get '2014-04-22'.
We are aware of this problem and have recently added time zone support to the Database nodes. Please adjust the time zone within the Database Reader configuration dialog to your local time zone. The underlying problem is that KNIME's date/time cell does convert date and times into UTC. This can be fixed by selecting your current time zone.