COUNT_DISTINCT

description

Syntax

COUNT_DISTINCT(expr)

用于返回满足要求的行的数目，或者非NULL行的数目

example

MySQL > select count_distinct(query_id) from log_statis group by datetime;
+----------------------------+
| count_distinct(`query_id`) |
+----------------------------+
|                        577 |
+----------------------------+

keyword COUNT_DISTINCT,COUNT,DISTINCT