后,我想在8由AVG值>摸索,像这样Where语句ORDER BY语句
SELECT avg(students_subject.nota) as avg, students.name
FROM students_subject
left JOIN studentsON students.id=students_subject.id_alumno
GROUP BY students_subject.id_student
where avg > 8;
后,我想在8由AVG值>摸索,像这样Where语句ORDER BY语句
SELECT avg(students_subject.nota) as avg, students.name
FROM students_subject
left JOIN studentsON students.id=students_subject.id_alumno
GROUP BY students_subject.id_student
where avg > 8;
与GROUP BY比较时使用HAVING。 其中不能与聚合函数一起使用。您的查询将是这样的:
SELECT avg(students_subject.nota) as avg, students.name
FROM students_subject
left JOIN studentsON students.id=students_subject.id_alumno
GROUP BY students_subject.id_student
HAVING avg > 8;
谢谢!工作也很好 –
后要求使用having
子句引用聚合函数条件:
SELECT avg(students_subject.nota) as avg, students.name
FROM students_subject
left JOIN students ON students.id=students_subject.id_alumno
GROUP BY students_subject.id_student
having avg(students_subject.nota)> 8;
谢谢!工作也很好! –
参考网站w3schools
语法
SELECT column_name(s)
FROM table_name
WHERE condition
GROUP BY column_name(s)
HAVING condition
ORDER BY column_name(s);
例
SELECT COUNT(CustomerID), Country
FROM Customers
GROUP BY Country
HAVING COUNT(CustomerID) > 5;
这里有一些例子:http://stackoverflow.com/文档/ mysql/3523/group-by#t = 201705031558494748459 –