从MySQL获取记录

Question

我有2个表：progress和student。 progress包含字段semester，idStudent，hasFirstAttestation和hasSecondAttestation。 我需要从progress获得那些学生最长学期且{Attestation = 0}的idStudent。 以下是我的查询示例，但它不起作用：

SELECT progress.idStudent FROM monitoring.progress 
WHERE hasFirstAttestation = 0 AND hasSecondAttestation = 0 
AND semester = 
    (SELECT MAX(`semester`)
        FROM monitoring.progress WHERE progress.idStudent = student.idStudent);

Answer 1

我想你忘了在FROM Clause中提到连接表

SELECT idStudent 
FROM monitoring.progress 
WHERE hasFirstAttestation = 0 AND hasSecondAttestation = 0 
AND semester = (SELECT MAX(semester) FROM monitoring.progress, monitoring.student 
WHERE progress.idStudent = student.idStudent);

Answer 2

SELECT progress.idstudent 
FROM   monitoring.progress 
WHERE  hasfirstattestation = 0 
   AND hassecondattestation = 0 
   AND semester = (SELECT Max(`semester`) 
                   FROM   monitoring.progress,monitoring.student
                   WHERE  progress.idstudent = student.idstudent);