我在MS Access中有两个表。一个约会表和一个插槽表。像这样:
现在我想从插槽表中选择每条记录,如果在约会表中有一条TeacherID =“CR”的记录,我希望它显示StudentID。
这是我到目前为止的SQL:
SELECT Slot.SlotNumber, Slot.SlotTime, Appointment.TeacherID
FROM Slot LEFT JOIN Appointment ON Slot.SlotNumber = Appointment.SlotNumber
WHERE Appointment.TeacherID="CR"
但是,这仅选择Appointment表中有记录的插槽。有什么建议?提前谢谢!
答案 0 :(得分:1)
如果我理解你的话。您不需要where
语句。而是把它放在LEFT JOIN
中。像这样:
SELECT
Slot.SlotNumber,
Slot.SlotTime,
Appointment.TeacherID
FROM
Slot
LEFT JOIN Appointment
ON (Slot.SlotNumber = Appointment.SlotNumber
AND Appointment.TeacherID="CR")