MySQL supports sub-second precision (actually microsecond) for DATETIME, TIMESTAMP and TIME types since version 5.6.4 (see http://dev.mysql.com/doc/refman/5.6/en/fractional-seconds.html), together with a recent MySQL C connector.

However there is a bug in qsql_mysql.cpp where there is a confusion between milli and microseconds when storing a datetime into database:

myTime->second_part = time.msec();

should become:

myTime->second_part = time.msec()*1000;

This patch works fine on my machine (tested only with DATETIME fields).