Free DATABRICKS-CERTIFIED-DATA-ANALYST-ASSOCIATE Web TestEngine Demo

Q17 Single choice

A data analyst needs to quickly estimate the number of unique user sessions in a dataset containing billions of records on Databricks SQL. Due to performance constraints, the analyst must ensure the query runs efficiently and delivers results with acceptable accuracy.

What is the primary advantage of using APPROX_COUNT_DISTINCT instead of COUNT_DISTINCT in this scenario?

A
APPROX_COUNT_DISTINCT provides exact counts, while COUNT DISTINCT only provides estimates.
B
APPROX_COUNT_DISTINCT can only be used with string columns, while COUNT DISTINCT works with numeric columns.
C
APPROX_COUNT_DISTINCT uses the HyperLogLog++ algorithm to provide fast approximate counts with configurable accuracy (default 5% relative standard deviation).
D
APPROX_COUNT_DISTINCT requires less memory by storing only the first 1000 unique values.

DATABRICKS-CERTIFIED-DATA-ANALYST-ASSOCIATE Web TestEngine demo