宝安22期-陈琪-3.13作业

1， select chinese,english,math from grade where class=1832

2， select chinese,class from grade where 80<chinese<90 and class=1833;


3，select * from grade  where id  limit 4,9;

4， select * from grade where name and  english=98 or math=77 AND class=1832;
5 ，select * from grade where class=1832 order by chinese desc;

6， select * from grade where chinese<80 or  math<80;

7，Select * from grade where chinese is null;

8，Select * from grade where chinese <60;

9，select avg(math) from grade where class=1832;
     select avg(math) from grade where class=1833;

10、 select sum(chinese) from grade where class=1832;
        select sum(chinese) from grade where class=1833;

11、update grade set chinese=60 where chinese<60;
12、select * from grade  where (math>70 and english>70 and chinese>70) and age or name;  

13、 select * from grade  where english>70 and (math>60 or chinese>60);

14、select count(class) from grade where class=1832;
       select count(class) from grade where class=1833;

15、select count(math) from grade where math>80 and class=1832;
       select count(math) from grade where math>80 and class=1833;


16、select max(english)  from grade where class=1832;
       select max(english)  from grade where class=1833;

17、 alter table grade add (history int (3),geography(3),politics(3));