Friday, August 31, 2012

Random Sampling in Oracle using Sample Clause

In an earlier post about "Random Sampling using SQL", we use functions mode and dbms_random.random to randomly sample 30% of records.  This can also be done easily with oracle sample clause as the following:
select * from TBL_TEST sample(30);
Sample clause is also a great way to test the performance of a query before we run it on large tables.


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Jay Zhou, PhD. said...