mysql»ù´¡½Ì³Ì£ºº¯Êý²éѯÓï¾ä£¬²Î¿¼±íscore£¬±íÖаüÀ¨id,stu_id,c_name,gradeµÈ¼¸ÁУ¬¶ÔÕâ¸ö±í½øÐк¯Êý²éѯ

count()ÓÃÀ´Í³¼Æ¼Ç¼µÄÌõÊý

mysql> select count(*) from score;

mysql> select count(*) from score where stu_id=901;

sum()ÇóºÍº¯Êý

mysql> select sum(grade) from score;

mysql> select id,sum(grade) from score where stu_id=901;

avg()Çóƽ¾ùÖµº¯Êý

mysql> select avg(grade) from score where c_name='¼ÆËã»ú';

mysql> select c_name,avg(grade) from score group by c_name;

max()Çó×î´óÖµº¯Êý

mysql> select c_name,max(grade) from score where c_name='Ó¢Óï';

mysql> select c_name,max(grade) from score group by c_name;

min()Çó×îСֵº¯Êý

mysql> select c_name,min(grade) from score where c_name='ÖÐÎÄ';

mysql> select c_name,min(grade) from score group by c_name;

ConcatÆ´½Óº¯Êý

mysql> select Concat(c_name, '(', stu_id, ')')

-> from score order by stu_id;