Determine the size of a SQL result set in KB

Question

I am hoping to find how I can get the kb size of a result set in OracleDB. I am not an sysadmin, but often run queries that return over 100k rows and I would need to find a

Answer 1

Generally, you would replace your column list with a count(*) to return the row count.

I'm not sure how well that would work on really complicated queries with many joins and such but, for simpler queries, it should be fine. Replace:

select a,b,c from t where a > 7;

with

select count(*) from t where a > 7;

That will give you the row count before you run the real query. Just keep in mind there's a chance the data may change between your count query and real query (hopefully not too much). Knowledge of the data properties will allow you to approximate kilobytes from row count.