Lets say I have a result set from a query that comprises of 50 million records. Does adding a FETCH FIRST 100 ROWS ONLY clause, limit the query from building the result set of 50 million records? For example, the query will only build a result set of 100 records and return it? Or will the query still need to build a result set of 50 million records, and then only return the first 50 rows from it?

Just trying to understand the mechanics of using the FECTH clause.