This topic describes the syntax of mathematical statistics functions and provides usage examples.
Basic syntax
| Function | Description |
|---|---|
| corr(key1, key2) | Calculates the correlation between two specific columns.
Valid values: 0 to 1. |
| covar_pop(key1, key2) | Calculates the population covariance of two specific columns. |
| covar_samp(key1, key2) | Calculates the sample covariance of two specific columns. |
| regr_intercept(key1, key2) | Returns the linear regression intercept of input values. key1 is the dependent value and key2 is the independent value. |
| regr_slope(key1, key2) | Returns the linear regression slope of input values. key1 is the dependent value and key2 is the independent value. |
| stddev(key) | Calculates the sample standard deviation of the key column. This function is equivalent to the stddev_samp function. |
| stddev_samp(key) | Calculates the sample standard deviation of the key column. |
| stddev_pop(key) | Returns the population standard deviation of the key column. |
| variance(key) | Calculates the sample variance of the key column. This function is equivalent to the var_samp function. |
| var_samp(key) | Calculates the sample variance of the key column. |
| var_pop(key) | Calculates the population variance of the key column. |
Examples
- Example 1: Return the correlation of two specific columns.
- Query statement
* | SELECT corr(request_length, request_time) - Query and analysis results
- Query statement
- Example 2: Query the sample standard deviation and population standard deviation of
pre-tax income.
- Query statement
* | SELECT stddev(PretaxGrossAmount) as "sample standard deviation", stddev_pop(PretaxGrossAmount) as "population standard deviation", time_series(__time__, '1m', '%H:% I:%s', '0') AS time GROUP BY time - Query and analysis results
- Query statement