Good day, Joe.
J> "Fictional" is IMO not a good choice for
J> describing aggregates, because it means "a story that is not true",
J> whereas an SQL aggregate is something that is "true" (in the
J> mathematical sense) but is "derived" from other values.
It means, that TML and DDL aggregates have different sense.
J> (I'm not sure what the special symbols mean -- maybe what you need first
J> is a syntax reference for TML)
http://sql4.by.ru/site/sql40/en/author/tree_eng.htm
J> sum of the employees salaries?
yes.
"amount" is quantity of employees
J> How do I see employees in just one department?
department[id="1"].employee >>;
or
department[name="Technical"].employee >>;
J> How do I see a single employee?
employee[id="31"] >>;
or
employee[name="Tomson"] >>; -- maybe several employee with surname Tomson
J> How do I see all employees that have a salary greater than 3500
department.employee[salary>3500] >>;
J> ordered by their names?
Now sorting for output is absent.
I'm not sure, that it's necessary,
but i already thought about this and continue to think.
J> How do I actually retrieve SUM(salary)
Declare field "sum" as not fictional.
You can always declare field "sum" as not fictional and
put sign "#" before field to prevent output of field.
J> GROUP BY department?
It is always "group by", because it is field of record "department"
P.S.
If you don't like to put sign "#" before field "sum",
or you don't like absence of sorting NOW
(it's possible, that i add sorting),
then remember, that advantage is absence of gasket
(php, etc) between DBMS and external world.
That is more important for un-experienced users.
Dmitry Turin
http://html6.by.ru
http://sql4.by.ru
http://computer2.by.ru
