They provide simple statistics on the number of records falling in certain categories including the number of rows, the number of null values, the number of distinct and unique values, the number of duplicates, or the number of blank fields.
- Blank Count: counts the number of blank rows. A "blank" is a non null textual data that contains only white space. Note that Oracle does not distinguish between the empty string and the null value.
- Default Value Count: counts the number of default values.
- Distinct Count: counts the number of distinct values of your column.
- Duplicate Count: counts the number of values appearing more than once. You have the relation: Duplicate count + Unique count = Distinct count. For example, a,a,a,a,b,b,c,d,e => 9 values, 5 distinct values, 3 unique values, 2 duplicate values.
- Null Count: counts the number of null rows.
- Row Count: counts the number of rows.
- Unique Count: counts the number of distinct values with only one occurrence. It is necessarily less or equal to Distinct counts.