S) scan ,rollup and dedup with null key and unique key
Scan with null key ---11 rec Rollup with null key –1 record( depends if the data is sorted then last if data is not sorted then fst record) Dedup with null key —( keep fst )—1 record Dedup with null key —( keep lst )—1 record Dedup with null key —( keep unique)—0 record ( key didn’t get the unique record bcoz it treats every record is one group