genmai.go
func (db *DB) Where(cond interface{}, args ...interface{}) *Condition {
	return newCondition(db).Where(cond, args...)
}
func (db *DB) Where(cond interface{}, args ...interface{}) *Condition {
	return newCondition(db).Where(cond, args...)
}
// Where returns a new Condition of "WHERE" clause.