如何在mysql中創建條件（使用'if'）？

此代碼工作正常找到特定日期內的可用空間，但它不工作表明已經預訂和取消如何在mysql中創建條件（使用'if'）？

的「酒店」有4間房間和他們的1房間已經訂滿了取消

所以即使我做了取消，select方法仍然給我3個結果。也許是因爲第二個AND仍在運行。所以基本上我需要的是

檢查，如果房間在選定日期
如果已經預訂預訂，檢查其取消
，如果它已經被取消，或沒有預訂顯示它。否則不

SELECT RoomNo, NightCost 
FROM room, room_types, booking 
WHERE typeid = fk1_typeid 
and double_bed=1 
and single_bed=0 
AND canceled = '1' in 
    (SELECT canceled 
    from booking, room_booking 
    where bookingid = fk2_bookingid) 
AND RoomNo not in 
    (SELECT fk1_RoomNo 
    FROM room_booking 
    WHERE '2010-04-02' between Check_in 
    and Check_Out or 
    '2010-04-03' between Check_in 
    and Check_Out) ;

我試圖儘可能清楚，如果需要的話

來源

2010-03-24 Audel

SELECT * 
FROM room 
JOIN room_types 
ON  typeid = fk1_typeid 
WHERE double_bed = 1 
     AND single_bed = 0 
     AND roomNo NOT IN 
     (
     SELECT fk1_roomno 
     FROM room_booking 
     WHERE check_out >= '2010-04-02' 
       AND check_in <= '2010-04-03' 
       AND NOT canceled 
     )

來源

2010-03-24 19:21:01 Quassnoi

太感謝許多！！它的工作原理，我認爲我需要嘗試和解釋更多 – Audel 2010-03-24 19:49:35

一間間佔據我將圍繞透露更多的細節2010-04-02 and 2010-04-04 if
- 有人2010-04-03
- 前的檢查中，並有人是不是要2010-04-02
- 之前退房和room_booking沒有被取消。
一個房間是免費的，當它沒有被佔用

SELECT R.RoomNo, R.NightCost 
    FROM room as R 
    JOIN room_types as RT ON RT.typeid = R.fk1_typeid 
WHERE (R.single_bed=0 and R.double_bed=1) 
    AND R.roomNo NOT IN (
     SELECT RB.fk1_roomno 
      FROM room_booking as RB 
     WHERE (RB.check_out >= '2010-04-02') 
      AND (RB.check_in <= '2010-04-03') 
      AND NOT (RB.canceled=1) 
    )

這正是Quassnoi我之前說的..嘆息:-)

來源

2010-03-24 19:56:09 lexu

如何在mysql中創建條件（使用'if'）？

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