mysql student achievement table example

# Zhang query the lowest score of each student more than 60 school number and name

SELECT r.studentno,studentname
FROM result r
INNER JOIN student s
ON r.`studentno`=s.`studentno`
WHERE s.`studentname` LIKE '张%' 
GROUP BY r.`studentno`
HAVING MIN(r.`score`)>60;

# Query the name of the student's birthday in '1988-1-1' after the name and professional

SELECT studentname,m.`majorname`
FROM student s
INNER JOIN major m 
ON s.`majorid`=m.`majorid`;
WHERE DATEDIFF(borndate,'1988-1-1')>0;

# Query each professional is the number of boys and number of girls were much

SELECT COUNT(*),sex,majorid
FROM student
GROUP BY sex,majorid;

or

SELECT (SELECT COUNT(*) FROM student WHERE sex='男' AND s.majorid=majorid ),
             (SELECT COUNT(*) FROM student WHERE sex='女' AND s.majorid=majorid),
             majorid
FROM student s
GROUP BY majorid;

# Inquiry and professional students as Cuishan lowest score

SELECT MIN(score)
FROM result r
WHERE r.`studentno`IN
(SELECT studentno
    FROM student s
    WHERE s.`majorid` =(
        SELECT majorid
        FROM student
        WHERE studentname='张翠山'
        )
)

# Query than 60 points the student's name, password, professional name

SELECT studentname,loginpwd,majorname
FROM student s
INNER JOIN major m
ON s.`majorid`=m.`majorid`
INNER JOIN result r
ON r.`studentno`=s.`studentno`
WHERE r.`score`>60;

# Grouped by mailbox digits, the number of students in each query

SELECT COUNT(*)
FROM student
GROUP BY LENGTH(email);

# Inquiry student name, professional name, score

SELECT studentname,majorname,score
FROM student s
INNER JOIN major m
ON s.`majorid`=m.`majorid`
INNER JOIN result r
ON r.`studentno`=s.`studentno`;

# Any professional inquiry no students were connected with the realization of the left and right connections

SELECT majorname
FROM major m
LEFT OUTER JOIN student s
ON m.`majorid`=s.`majorid`
WHERE s.`majorid` IS NULL;  

# Inquiry number of students did not score

SELECT COUNT(*)
FROM student s
LEFT JOIN result r ON s.studentno=r.studentno

WHERE r.id IS NULL;