389 B
Executable File
389 B
Executable File
COUNT_DISTINCT
Syntax
COUNT_DISTINCT(expr)
Description
用于返回满足要求的行的数目,或者非NULL行的数目
Examples
MySQL > select count_distinct(query_id) from log_statis group by datetime;
+----------------------------+
| count_distinct(`query_id`) |
+----------------------------+
| 577 |
+----------------------------+