與分頁SQL SQL ROW_NUMBER（）問題

Question

我使用ROW_NUMBER()函數從數據庫表中獲得50 50個項目。
@From參數是從哪個行開始抓取50行。 （第一次是51,101,151等）
我將參數@CityId傳遞給存儲過程，如果數據庫中的前60行是cityId=1和cityId = 2在第61行，則此存儲過程不返回結果。
但是，如果我通過@From參數51比它返回我的結果。 我在這裏做錯了什麼？

SELECT RowConstrainedResult.* 
FROM (SELECT ROW_NUMBER() OVER 
(ORDER BY f.ItemCreatedOnDate DESC) AS RowNum, 
f.* 
FROM (
SELECT 
     t.ItemIdId, 
     t.ItemTypeId, 
     t.CreatedOnDate as ItemCreatedOnDate, 
     t.CityId as CityId 
FROM dbo.Items as t 
) f) AS RowConstrainedResult 
WHERE RowNum >= @From 
    AND RowNum < @From + 50 
    AND CityId = @CityId 

Answer 1

在您的版本中，ROW_NUMBER()正在枚舉所有行。將cityid的謂詞移動到最裏面的選擇，ROW_NUMBER()將僅枚舉其中cityid = 2的行。

SELECT RowConstrainedResult.* 
FROM (
    SELECT ROW_NUMBER() OVER (ORDER BY f.ItemCreatedOnDate DESC) AS RowNum, 
      f.* 
    FROM (
      SELECT t.ItemIdId, 
       t.ItemTypeId, 
       t.CreatedOnDate as ItemCreatedOnDate, 
       t.CityId as CityId 
      FROM dbo.Items AS t 
      WHERE CityId = @CityId 
     ) AS f 
    ) AS RowConstrainedResult 
WHERE RowNum >= @From AND 
     RowNum < @From + 50 

Answer 2

我猜你想要做的是在內部選擇查詢CityId過濾器，像這樣：

SELECT RowConstrainedResult.* 
FROM (SELECT ROW_NUMBER() OVER 
(ORDER BY f.ItemCreatedOnDate DESC) AS RowNum, 
f.* 
FROM (
SELECT 
     t.ItemIdId, 
     t.ItemTypeId, 
     t.CreatedOnDate as ItemCreatedOnDate, 
     t.CityId as CityId 
FROM dbo.Items as t 
WHERE CityId = @CityId 
) f) AS RowConstrainedResult 
WHERE RowNum >= @From 
    AND RowNum < @From + 50