select * from Student t where t.s_name like '王%';
SELECT COUNT(s_name) '学生的姓名' from Student WHERE s_name LIKE '王%';
SELECT s_name,COUNT(s_name) '出现的次数' FROM Student GROUP BY s_name HAVING COUNT(s_name) < 0;
SELECT s_name,COUNT(s_name) '出现的次数' FROM Student GROUP BY s_name HAVING s_name LIKE '王%';
-- from on jion where GROUP BY having SELECT DISTINCT ORDER BY LIMIT;
SELECT * from Score;
SELECT SUM(s_score) FROM Score WHERE c_id = '02';
SELECT * FROM Student;
SELECT * FROM Course;
SELECT * from Score;
SELECT count(DISTINCT(s_id)) from Score;
-- SELECT DISTINCT * from Score;
--
SELECT * from Student t WHERE t.s_id in (SELECT DISTINCT(s_id) FROM Score);
SELECT c_id,MAX(s_score) FROM Score GROUP BY c_id;
SELECT
*
FROM
Course c
LEFT JOIN (
SELECT
c_id,
MAX( s_score ),
MIN(s_score)
FROM
Score
GROUP BY
c_id
) s ON s.c_id = c.c_id;
SELECT * FROM Course;
SELECT c_id,count(c_id) from Score GROUP BY c_id;
SELECT * from Student;
SELECT
a.s_sex,a.partition,b.total
FROM
(SELECT s_sex,COUNT(s_sex) As 'partition' FROM Student GROUP BY s_sex) a
(SELECT COUNT(s_sex) As 'total' FROM Student) b
SELECT
s_sex,
n,
ROUND( n / s * 100, 4)
FROM
(
SELECT
*
FROM
( SELECT s_sex, count( 1 ) n FROM Student GROUP BY s_sex ) t1
INNER JOIN ( SELECT count( 1 ) s FROM Student ) t2 ON 1 = 1
)a;
SELECT s_id,AVG(s_score) from Score GROUP BY s_id HAVING AVG(s_score) > 60;
SELECT s_id,COUNT(c_id) FROM Score GROUP BY s_id HAVING COUNT(c_id) >2;
SELECT s_name,COUNT(s_name) FROM Student GROUP BY s_name HAVING COUNT(s_name) =2;