预约检查的SQL查询

Question

我有2个表，Facility和Reservation表。

设施表包含，

• FacilityID
• 类型
• 名称
• 状况

预订表，

• ID
• MEMBERID
• FacilityID
• 入住日期
• 入住时间

这是我的查询，它只返回保留的详细信息。如何使查询返回那些未预留的设施详细信息？

SELECT Facility.[Facility Name], Facility.[Facility Type] 
FROM Facility INNER JOIN Reservation on Facility.FacilityID = Reservation.FacilityID
WHERE Reservation.FacilityID = (
    SELECT FacilityID 
    FROM Reservation 
    WHERE MemberID = '" & txtMemberID.Text & "' 
    AND [Check-in date] ='" & lstDate.SelectedItem.ToString & "')

Answer 1

您可以使用LEFT OUTER JOIN和IS NULL仅返回Reservation表中没有记录的行。

以下查询将返回FacilityID，MemberID和Check-In日期的Reservation表中没有匹配项的所有工具。如果您想查看他们是否有任何会员的预订和任何入住日期，您可以删除会员ID和登记日期部分

SELECT Facility.[Facility Name], Facility.[Facility Type] 
FROM Facility 
    LEFT OUTER JOIN Reservation on Facility.FacilityID = Reservation.FacilityID
    AND MemberID = '" & txtMemberID.Text & "' // pull in based on certain member
    AND [Check-in date] ='" & lstDate.SelectedItem.ToString & "') // pull in based on certain date
WHERE Reservation.ID IS NULL