SELECTstatement具有可變WHERE

Question

我想創建一個SELECT語句中帶有可互換，其中內其聲明我已經拿到了2次嘗試不工作來展示你嘗試瞭解我試圖實現

變量@holidayType確定用戶已預訂了什麼類型的假期，我想這也確定WHERE語句運行

下面

是我第一次嘗試

IF @HolidayType = 'P' 
     BEGIN 
      WHERE Holidays.Type <> 'A' 
      AND Holidays.Type <> 'DE' 
     END 
    ELSE 
     BEGIN 
      IF @HolidayType = 'A' 
       BEGIN 
        WHERE Holidays.Type <> 'P' 
        AND  Holidays.Type <> 'DE' 
       END 
      ELSE 
       BEGIN 
        WHERE Holidays.status <> 'DE' 
       END 
     END 

下面是我的第二個學嘗試T（更清楚一點）

WHERE 
    (
    CASE @HolidayType 
     WHEN 'A' THEN (Holidays.Type <> 'P' AND Holidays.Type <> 'DE') 
     WHEN 'P' THEN (Holidays.Type <> 'A' AND Holidays.Type <> 'DE') 
     WHEN 'F' THEN (Holidays.status <> 'DE') 
    END 
    ) 

選擇前兩者都比較簡單，它只是添加了Where聲明，對我來說是很難證明的。

Answer 1

我提出以下解決方案。或許筆者會更清楚，因爲它是接近他的問題：

WHERE 
    (
    CASE @HolidayType 
     WHEN 'A' THEN CASE WHEN (Holidays.Type <> 'P' AND Holidays.Type <> 'DE') THEN 1 ELSE 0 END 
     WHEN 'P' THEN CASE WHEN (Holidays.Type <> 'A' AND Holidays.Type <> 'DE') THEN 1 ELSE 0 END 
     WHEN 'F' THEN CASE WHEN (Holidays.status <> 'DE') THEN 1 ELSE 0 END 
    END = 1 
    ) 

Answer 2

WHERE 
    (@HolidayType = 'A' AND Holidays.Type <> 'P' AND Holidays.Type <> 'DE') 
    OR 
    (@HolidayType = 'P' AND Holidays.Type <> 'A' AND Holidays.Type <> 'DE') 
    OR 
    (@HolidayType = 'F' AND Holidays.status <> 'DE') 

Answer 3

嘗試使用這樣的：

WHERE (@HolidayType = 'A' AND Holidays.Type <> 'P' AND Holidays.Type <> 'DE') OR 
     (@HolidayType = 'P' AND Holidays.Type <> 'A' AND Holidays.Type <> 'DE') OR 
     (@HolidayType = 'F' AND Holidays.status <> 'DE')