I have two table , one name of student and other one have lesson of student , I need to find student with have two or one lesson .
table 1 :(students)
id , name , family , birth , mobile
table 2 : (lessons)
id , studentID , name
and my code is
SELECT t.* FROM students AS t LEFT JOIN lessons AS tr ON t.id = tr.userID WHERE count(tr.*) = 1
这是您的查询:
SELECT students.name, COUNT(studentID) AS CANT FROM students, lessons WHERE students.id = studentID GROUP BY studentID HAVING CANT = 1 OR CANT = 2
尝试这个
SELECT s.id , s.name , family , birth , mobile FROM student s, lessons l WHERE s.id = l.studentID AND (SELECT COUNT(*) FROM lessons WHERE studentID = student.id) as totalLessons BETWEEN 1 AND 2 GROUP BY s.id
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