@Override
    public Q with(Path<?> alias, SubQueryExpression<?> query) {
        Expression<?> expr = ExpressionUtils.operation(alias.getType(), SQLOps.WITH_ALIAS, alias, query);
        return queryMixin.addFlag(new QueryFlag(QueryFlag.Position.WITH, expr));
    }
Creates an union expression for the given subqueries

@param <RT>
@param alias alias for union
@param sq subqueries
@return the current object
querydsl-sql/src/main/java/com/querydsl/sql/ProjectableSQLQuery.java