| --- |
| { |
| "title": "COUNT", |
| "language": "en" |
| } |
| --- |
| |
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| |
| ## COUNT |
| ### Description |
| #### Syntax |
| |
| `COUNT([DISTINCT] expr)` |
| |
| |
| Number of rows used to return the required rows |
| |
| ### 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 |