AVG

description

Syntax

AVG([DISTINCT] expr)

用于返回选中字段的平均值

可选字段DISTINCT参数可以用来返回去重平均值

example

  1. mysql> SELECT datetime, AVG(cost_time) FROM log_statis group by datetime;
  2. +---------------------+--------------------+
  3. | datetime | avg(`cost_time`) |
  4. +---------------------+--------------------+
  5. | 2019-07-03 21:01:20 | 25.827794561933533 |
  6. +---------------------+--------------------+
  7. mysql> SELECT datetime, AVG(distinct cost_time) FROM log_statis group by datetime;
  8. +---------------------+---------------------------+
  9. | datetime | avg(DISTINCT `cost_time`) |
  10. +---------------------+---------------------------+
  11. | 2019-07-04 02:23:24 | 20.666666666666668 |
  12. +---------------------+---------------------------+

keywords

AVG