mysql中常見的分組函數(shù)有sum()求和函數(shù)、avg()求平均值函數(shù)、max()求最大值函數(shù)、min()求最小值函數(shù)、和count()計算個數(shù)函數(shù)幾種，使用方法如下：
1.sum() 求和
select sum(salary) from employees;
2.avg() 求平均值
select avg(salary) from employees;
3.max() 求最大值
select max(salary) from employees;
4.min() 求最小值
select min(salary) from employees;
5.count() 計算個數(shù)
select count(commission_pct) from employees;
