Summarizes the information of distinct non-NULL values and materializes the result set in a
LONG VARBINARY synopsis object. The calculated result is within a specified range of error tolerance. You save the synopsis object in a Vertica table for use by
APPROXIMATE_COUNT_DISTINCT_SYNOPSIS ( expression[, error‑tolerance] )
|expression||Value to evaluate using any data type that supports equality comparison.|
Numeric value that represents the desired percentage of error tolerance, distributed around the value returned by this function. The smaller the error tolerance, the closer the approximation.
You can set
If you omit this argument, Vertica uses an error tolerance of 1.25(%).
For more details, see
DISTINCT aggregates cannot be in the same query block.