COUNT

COUNT

Description

Syntax:

COUNT([DISTINCT] expr)

This function is used to return the number of rows that meet the specified requirements.

Example

MySQL > select count(*) from log_statis group by datetime;
+----------+
| count(*) |
+----------+
| 28515903 |
+----------+

MySQL > select count(datetime) from log_statis group by datetime;
+-------------------+
| count(`datetime`) |
+-------------------+
|         28521682  |
+-------------------+

MySQL > select count(distinct datetime) from log_statis group by datetime;
+-------------------------------+
| count(DISTINCT `datetime`)    |
+-------------------------------+
|                       71045   |
+-------------------------------+

Keywords

COUNT