0 - 2 of 2 tags for random amp sample

The accuracy of sample statistics has been greatly improved over the last Teradata releases. So I usually try to use sample stats on most of the big tables and I found them to be reliable on many columns, not only the officially recommended unique or nearly-unique columns, e.g. on DATEs.

Hi all,

        I would like to know to what level statistics on a column(s) is useful when the column(s) is used in a non-equality constraint (using <> operator)?

I believe the optimizer can derieve the record count that will qualify by using the following expression