#分組函數(shù):用作統(tǒng)計(jì)使用,可嵌套使用
USE myemployees;
#sum 求和
SELECT SUM(salary) FROM employees;
#avg 求平均
SELECT AVG(salary) FROM employees;
#max 求最大值
SELECT MAX(salary) FROM employees;
#min 求最小值
SELECT MIN(salary) FROM employees;
#count 計(jì)算個(gè)數(shù)
SELECT COUNT(salary) FROM employees;