1、COUNT()函数
SELECT COUNT(*) FROM t_grade;
SELECT COUNT(*) AS total FROM t_grade;
SELECT stuName,COUNT(*) FROM t_grade GROUP BY stuName;
2、SUM()函数
3、AVG()函数
SELECT stuName,AVG(score) FROM t_grade WHERE stuName="张三";
SELECT stuName,AVG(score) FROM t_grade GROUP BY stuName;
4、MAX()函数
SELECT stuName,course,MAX(score) FROM t_grade WHERE stuName="张三";
SELECT stuName,MAX(score) FROM t_grade GROUP BY stuName;
5、MIN()函数
SELECT stuName,course,MIN(score) FROM t_grade WHERE stuName="张三";
SELECT stuName,MIN(score) FROM t_grade GROUP BY stuName;
