SQL：過程沒有得到一個日期空

Question

我執行這樣一個過程：

EXEC myProcedure @name = 'Smith', @dateDeleted = NULL 

我需要所有沒有被刪除的日期史密斯。

這是程序：

CREATE PROCEDURE [dbo].[myProcedure] 
    @name VARCHAR(8000) = NULL 
,@dateDeleted VARCHAR(8000) = NULL 

AS 
BEGIN 
SET NOCOUNT ON; 
    WITH t 
    (name 
    ,dateDeleted 
    ) 

AS 
(
    SELECT DISTINCT 
    name,dateDeleted FROM mytable 
    WHERE 
    (@name IS NULL OR @name = name) 
    AND (@dateDeleted IS NULL OR CONVERT(DATETIME, @dateDeleted, 102) = dateDeleted) 

) 

執行後我把所有的史密斯，但它不支付任何注意dateDeleted = NULL。我GE所有的史密斯不管他們是否有刪除日期

我該如何解決這個問題？

感謝

Answer 1

的explantion在您的要求，如果你傳遞NULL，則條件總是true.Try這其中具有COALESCE表達子句：

WHERE (@name IS NULL OR @name = name) 
    AND (COALESCE(@dateDeleted, dateDeleted) IS NULL 
    OR CONVERT(DATETIME, @dateDeleted, 102) = dateDeleted) 

Answer 2

您需要設置

ANSI空值執行：

set ansi_nulls on 

然後執行查詢。

以下是此行爲

http://msdn.microsoft.com/en-us/library/ms188048.aspx