Hi. There is no way, via metadata, nor any way via any regular query
either. You could do a prior query, eg:

"select count(*) from mytable where ....."
and then do the real query "select what I want from mytable where ..."

But unless you have locked the table, some other process might
alter the contents of the table between the count and the
query. For some DBMSes and query types, the table and results
could change *while* the query was half-processed, so even the
DBMS doesn't know how many rows are going to be returned till
the last row is sent...

The only recourse is to know your data as well as you can,
make as selective a query as you can, and program the client
to handle whatever might come back. There is clever SQL that
will return 50 rows, and then the next 50 rows sucessively
till the data you wanted is done, but the syntax is enough
different for each DBMS that you should ask an expert in your
given DBMS to help write it.

Joe Weinstein at BEA Systems