@Override
    public <E> Q leftJoin(RelationalFunctionCall<E> target, Path<E> alias) {
        return queryMixin.leftJoin(target, alias);
    }
Add the given Expression as a query flag

@param position position
@param flag query flag
@return the current object
querydsl-sql/src/main/java/com/querydsl/sql/ProjectableSQLQuery.java