diff --git a/docs/querying/sql-aggregations.md b/docs/querying/sql-aggregations.md index 07a1183f151..cf436829712 100644 --- a/docs/querying/sql-aggregations.md +++ b/docs/querying/sql-aggregations.md @@ -66,7 +66,7 @@ In the aggregation functions supported by Druid, only `COUNT`, `ARRAY_AGG`, and |Function|Notes|Default| |--------|-----|-------| |`COUNT(*)`|Counts the number of rows.|`0`| -|`COUNT(DISTINCT expr)`|Counts distinct values of `expr`.

When `useApproximateCountDistinct` is set to "true" (the default), this is an alias for `APPROX_COUNT_DISTINCT`. The specific algorithm depends on the value of [`druid.sql.approxCountDistinct.function`](../configuration/index.md#sql). In this mode, you can use strings, numbers, or prebuilt sketches. If counting prebuilt sketches, the prebuilt sketch type must match the selected algorithm.

When `useApproximateCountDistinct` is set to "false", the computation will be exact. In this case, `expr` must be string or numeric, since exact counts are not possible using prebuilt sketches. In exact mode, only one distinct count per query is permitted unless `useGroupingSetForExactDistinct` is enabled.|`0`| +|`COUNT(DISTINCT expr)`|Counts distinct values of `expr`.

When `useApproximateCountDistinct` is set to "true" (the default), this is an alias for `APPROX_COUNT_DISTINCT`. The specific algorithm depends on the value of [`druid.sql.approxCountDistinct.function`](../configuration/index.md#sql). In this mode, you can use strings, numbers, or prebuilt sketches. If counting prebuilt sketches, the prebuilt sketch type must match the selected algorithm.

When `useApproximateCountDistinct` is set to "false", the computation will be exact. In this case, `expr` must be string or numeric, since exact counts are not possible using prebuilt sketches. In exact mode, only one distinct count per query is permitted unless `useGroupingSetForExactDistinct` is enabled.

Counts each distinct value in a [`multi-value`](../querying/multi-value-dimensions.md)-row separately.|`0`| |`SUM(expr)`|Sums numbers.|`null` if `druid.generic.useDefaultValueForNull=false`, otherwise `0`| |`MIN(expr)`|Takes the minimum of numbers.|`null` if `druid.generic.useDefaultValueForNull=false`, otherwise `9223372036854775807` (maximum LONG value)| |`MAX(expr)`|Takes the maximum of numbers.|`null` if `druid.generic.useDefaultValueForNull=false`, otherwise `-9223372036854775808` (minimum LONG value)|