@Override
    public <T> C setNull(Path<T> path) {
        columns.add(path);
        values.add(Null.CONSTANT);
        return (C) this;
    }
Execute the clause and return the generated keys as a ResultSet

@return result set with generated keys
querydsl-sql/src/main/java/com/querydsl/sql/dml/AbstractSQLInsertClause.java