I think this is what you want....
I have answered it on the other thread you have started:
what is the internal functionality top function ,
supose we fired a sql query " sel top 10 * from emp"
emp table having 100 record, it's picking the top 10 records directly from base table and giving the user ?
all table 100 records takeen to spool areya after filters top 10 records than giving the user ?
Without order by clause the database will return any 10 rows from the table, but this result may not be truely random. The random function does extra processing to generate a random result.
AFAIK, The 100 rows will not be taken to spool, simple 10 random rows will be selected and returned.