我有 3 个表(tblPreference
, tblCustomer
, tblCustomerPreference
),如下所示:
tblPreference:
ID | Name | DefaultValue
(int PK) | (nvarchar(100)) | (nvarchar(100))
-------------------------------
1 | Preference1 | 1
2 | Preference2 | Yes
3 | Preference3 | 1
tblCustomer:
CustomerID | ...
(int PK)
--------------------
1 | ...
2 | ...
3 | ...
tblCustomerPreference:
ID | CustomerID | PreferenceID | Value
(int PK) | (int) | (int) | (nvarchar(100))
-------------------------------------------------------
1 | 1 | 1 | 0
2 | 1 | 2 | Yes
3 | 2 | 1 | 0
4 | 2 | 2 | No
我正在创建此数据的数据透视,因此使用以下存储过程将其全部放在一行中,以便它始终拉回所有首选项,如果找到客户特定值,它将返回,否则返回默认值:
CREATE PROCEDURE [dbo].[usp_GetCustomerPreferences] @CustomerID int AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from interfering with SELECT statements.
SET NOCOUNT ON;
DECLARE @PivotColumns nvarchar(max)
DECLARE @PivotColumnsSelectable nvarchar(max)
SELECT @PivotColumns = COALESCE(@PivotColumns + ',','') + QUOTENAME(Preference.Name),
@PivotColumnsSelectable = COALESCE(@PivotColumnsSelectable + ',' + Char(10),'') + Preference.Source + '.' + QUOTENAME(Preference.Name) + ' AS ' + QUOTENAME(Preference.Name)
FROM (SELECT [Name],
'PreferencePivot' AS [Source]
FROM [dbo].[tblPreference]) Preference
DECLARE @sqlText nvarchar(max)
SELECT @sqlText = 'SELECT ' + @PivotColumnsSelectable + '
FROM (SELECT tblPreference.Name AS PreferenceName,
CASE
WHEN tblCustomerPreference.Value IS NOT NULL THEN tblCustomerPreference.Value
ELSE tblPreference.DefaultValue
END AS Value,
@innerCustomerID AS CustomerID
FROM tblCustomerPreference
RIGHT JOIN tblPreference ON tblCustomerPreference.PreferenceID = tblPreference.ID
WHERE (tblCustomerPreference.CustomerID = @innerCustomerID OR tblCustomerPreference.ID IS NULL)) data
PIVOT (MAX(Value)
FOR PreferenceName IN (' + @PivotColumns + ')) PreferencePivot'
EXECUTE sp_executesql @sqlText, N'@innerCustomerID int', @CustomerID
END
我遇到的问题是,当我查询 CustomerID 1 或 2 时,一切都按预期返回,所有值都按预期填充。但是,如果我查询 CustomerID 3,它将返回一个NULL
为其他客户填充的任何 PreferenceID。如果我在没有PIVOT
表达式的情况下运行查询,它将返回所有按预期填充的首选项。只有当我 PIVOT 数据时,数据才会NULL
蔓延。我希望我错过了一些简单的事情,但我没有看到错误。