關於預訂檢查的SQL查詢

Question

我有2個表，Facility和Reservation表。

設施表包含，

• FacilityID
• 類型
• 名稱
• 可用性

預約表，

• ID
• MEMBERID
• FacilityID
• 入住日期
• 入住時間

這裏是我的查詢它只能返回保留的細節。我怎樣才能使查詢返回這些毫無保留的設施細節？

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來僅返回預訂表中沒有記錄的行。

以下查詢將返回FacilityID，MemberID和Check-In日期的Reservation表中沒有匹配的所有設施。您可以刪除MEMBERID和入住的部分，如果你想看看他們是否有任何成員，任何登記入住日期預訂

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