After following, you can keep track of his dynamic information in a timely manner
Courses in the relevant section：Lecture 8
1、 isset() ：判断变量是否定义，是否存在； empty()：判断变量的值是否为空。 2、
function mysort($arr){ for($i=0;$i
select * from student order by class asc,score desc; select class,sum(if(score>=60,1,0)) jige,sum(if(score < 60,1,0) bujige from student group by class;
2021-01-190个赞
