Question

MaxPlaces列有时有一个值，有时只是NULL。我必须将此过程发送到C＃，但是当在代码中处理NULL时，代码将中断。

ISNULL无法正常工作，将出现以下错误：

其他信息：“ MaxPlaces”列不属于表 getLvLValue。

<div class = "row">
   <div class ="col-lg-12">
      //put your all child div here which you wants to keep in one row and properly divide the col-lg-12 for every child div
   </div>
</div>

有人可以帮助我解决这个问题。仅需要发送一个参数，如果MaxPlaces为NULL，则将值20发送到C＃。

谢谢！

Answer 1

它应该可以工作，但是您没有给结果列指定别名，请尝试以下操作：

ALTER PROCEDURE [dbo].[getLvLValue] 
       @LevID  nvarchar(100)
AS
BEGIN

SELECT a.BCID
     , a.CharacteristicID
     , b.CharacteristicName
     , a.LevID, ISNULL(b.MaxPlaces, '20') as MaxPlaces --here was the issue
FROM BCCharacteristics AS a INNER JOIN Characteristic AS b ON a.CharaID = b.CharaID
WHERE LevID =1 AND a.BCID = @LevelID AND a.CharaID = b.CharaID;

END

Answer 2

您应提供列名

ALTER PROCEDURE [dbo].[getLvLValue] 
   @LevID  nvarchar(100)

AS
BEGIN
SELECT a.BCID, a.CharacteristicID, b.CharacteristicName, a.LevID, ISNULL(b.MaxPlaces, '20') as MaxPlaces
 FROM BCCharacteristics AS a INNER JOIN Characteristic AS b ON a.CharaID = b.CharaID
WHERE LevID =1 AND a.BCID = @LevelID AND a.CharaID = b.CharaID;

END

如果值为NULL，则发送其他内容

2 个答案: