Select a random sample of results from a query result

Question

This question asks about getting a random(ish) sample of records on SQL Server and the answer was to use TABLESAMPLE. Is there an equivalent in Oracle 10?

Answer 1

SELECT * FROM TABLE_NAME SAMPLE(1)

Will give you olny an approximate 1% share rather than exactly 1/100 of the number of observations. The likely reason is than Oracle generates a random flag for each observation as to whether include in in the sample that it generates. The argument 1 (1%) in such a generation process takes the role of probability of each observation's being selected into the sample.

If this is true, the actual distribution of sample sizes will be binomial.