SQL Server存储过程可选参数，如果为null，则包括all

我有一个存储过程：

ALTER PROCEDURE [dbo].[GetCalendarEvents]
    (@StartDate datetime, 
     @EndDate datetime, 
     @Location varchar(250) = null)
AS
BEGIN
    SELECT * 
    FROM Events 
    WHERE EventDate >= @StartDate 
      AND EventDate <= @EndDate 
      AND (Location IS NULL OR Location = @Location)
END

我没有得到任何结果，因为还有其他位置不为null，并且由于location参数为null，我希望从所有位置获得结果

知道如何解决这个问题吗？

alterprocedure[dbo].[GetCalendarEvents]
ALTER PROCEDURE [dbo].[GetCalendarEvents]
( @StartDate DATETIME,
  @EndDate DATETIME,
  @Location VARCHAR(250) = NULL
)
AS
BEGIN
    SELECT  *
    FROM    events
    WHERE   EventDate >= @StartDate
            AND EventDate <= @EndDate
            AND Location = ISNULL(@Location, Location )
END

（@StartDate DATETIME，
@EndDate日期时间，
@位置VARCHAR（250）=空
)
作为
开始
挑选*
从事件中
其中EventDate>=@StartDate
而EventDate=@StartDate
而EventDate=@StartDate
和EventDate则
WHERE
子句中的部分应为

AND (@Location IS NULL OR Location=@Location)

试试这个

 SELECT * 
    FROM Events 
    WHERE EventDate >= @StartDate 
      AND EventDate <= @EndDate 
      AND Location = Case When LEN(@Location) > 0 Then  @Location Else Location End

选择*
从事件中
其中EventDate>=@StartDate
事件日期0，然后@Location Else Location End
使用动态sql查询可以轻松完成

ALTER PROCEDURE [dbo].[GetCalendarEvents]
(@StartDate datetime, 
 @EndDate datetime, 
 @Location varchar(250) = null)
AS
BEGIN
   DECLARE @SQL NVARCHAR(MAX);
   DECLARE @PARAMETER_DEFIINITION NVARCHAR(MAX);
   DECLARE @WHERE_PART NVARCHAR(MAX);

   SET @PARAMETER_DEFIINITION =' @StartDate DATETIME, @EndDate DATETIME, @Location VARCHAR(250) '

   SET @SQL ='SELECT * 
              FROM Events 
              WHERE EventDate >= @StartDate 
              AND EventDate <= @EndDate '

   IF @Location IS NOT NULL
   BEGIN
       SET @WHERE_PART = ' AND Location  = @Location '
   END    

   SET @SQL = @SQL + @WHERE_PART
   EXEC SP_EXECUTESQL @SQL, @PARAMETER_DEFIINITION, @StartDate, @EndDate, @Location
END

ALTER过程[dbo].[GetCalendarEvents]
（@StartDate datetime，
@EndDate日期时间，
@位置varchar（250）=空）
作为
开始
声明@SQL NVARCHAR（最大值）；
声明@PARAMETER_Definition NVARCHAR（最大值）；
声明@WHERE_零件NVARCHAR（最大值）；
设置@PARAMETER_definition='@StartDate-DATETIME、@EndDate-DATETIME、@Location-VARCHAR（250）'
SET@SQL='SELECT*
从事件中
其中EventDate>=@StartDate
谢谢，我会在10分钟内接受你的回答。成功了。祝您周末愉快如果events表中的Location列可以包含null，则此操作将失败。来自@TT的建议。这样更好。
 SELECT * 
    FROM Events 
    WHERE EventDate >= @StartDate 
      AND EventDate <= @EndDate 
      AND Location = Case When LEN(@Location) > 0 Then  @Location Else Location End

ALTER PROCEDURE [dbo].[GetCalendarEvents]
(@StartDate datetime, 
 @EndDate datetime, 
 @Location varchar(250) = null)
AS
BEGIN
   DECLARE @SQL NVARCHAR(MAX);
   DECLARE @PARAMETER_DEFIINITION NVARCHAR(MAX);
   DECLARE @WHERE_PART NVARCHAR(MAX);

   SET @PARAMETER_DEFIINITION =' @StartDate DATETIME, @EndDate DATETIME, @Location VARCHAR(250) '

   SET @SQL ='SELECT * 
              FROM Events 
              WHERE EventDate >= @StartDate 
              AND EventDate <= @EndDate '

   IF @Location IS NOT NULL
   BEGIN
       SET @WHERE_PART = ' AND Location  = @Location '
   END    

   SET @SQL = @SQL + @WHERE_PART
   EXEC SP_EXECUTESQL @SQL, @PARAMETER_DEFIINITION, @StartDate, @EndDate, @Location
END