Vlad, I have 100 or more complex sql with self made functions, 50% of them use
sql . Many of these are much more complex, than sample, I used in question
and all these works. And all these works, tested on big bases and so on.
I pretty sure , that VFP SQL is more weak, than SQL in Oracle, but it is still powerfull enough to make such queries. The clue was in something else.
For example, if I thrown function nsgn from query ( this function has not any query, this is just sign for sum) the query does not fail. It is strange, that it does not fail, if cursor is used instead of array in function.
It it rather difficalt to find other instrument ( not sql) for 'bookkeeper' tasks like
'main book', 'company balans' and so on. I have code written on Cliper for this and it 20-25 more big, than SQL ways of solutions. Unforturnatly I started DB programming after Cliper and mad hands are not trained on old fashion of db programming.