Spanner supports approximate aggregate functions for both GoogleSQL and

## Feature Feature Spanner supports approximate aggregate functions for both GoogleSQL and PostgreSQL dialects. These functions produce statistical estimates of distinct counts, allowing you to compute results faster and save resources on large datasets compared to exact aggregation. For more information, see approximate aggregate functions ([GoogleSQL](https://cloud.google.com/spanner/docs/reference/standard-sql/approximate%5Faggregate%5Ffunctions) and[PostgreSQL](https://cloud.google.com/spanner/docs/reference/postgresql/functions#approximate-aggregate)),[HyperLogLog++ functions](https://cloud.google.com/spanner/docs/reference/standard-sql/hll%5Ffunctions), and[Sketches](https://cloud.google.com/spanner/docs/reference/standard-sql/sketches).