Question

为什么查询＃2给我一个错误，将数据类型nvarchar转换为bigint？

查询＃1：

SELECT CAST(CAST(AsnNumber AS bigint) AS nvarchar(33)) AS AsnNumber 
FROM [DB1].Schema1.Table1 (nolock)

尝试使用转换，但得到相同的错误：

SELECT Convert(nvarchar(33), Convert(bigint, AsnNumber)) AS AsnNumber 
FROM [DB1].Schema1.Table1 (nolock)

查询＃2：

SELECT AsnNumber
FROM Query1
WHERE AsnNumber = '1777188'

此处AsnNumber的类型为nvarchar(33)，Table1

中为null

Answer 1

我把它作为一个答案，即使它没有真正回答这个问题，因为我无法在评论中恰当地适应这一点。

我针对SQL Server 2008运行此操作，我没有收到任何错误..

BEGIN
  DECLARE @t TABLE(AsnNumber NVARCHAR(33))

  INSERT INTO @t (AsnNumber) VALUES('1777188')
  INSERT INTO @t (AsnNumber) VALUES('1777189')

  SELECT AsnNumber FROM @t

  SELECT CAST(AsnNumber AS BIGINT) as AsnNumber 
  FROM @t
  WHERE AsnNumber = '1777188';

  SELECT CAST(CAST(AsnNumber AS BIGINT) AS NVARCHAR(33)) as AsnNumber 
  FROM @t
  WHERE AsnNumber = '1777188';

  SELECT query1.*
  FROM (SELECT CAST(CAST(AsnNumber AS BIGINT) AS NVARCHAR(33)) as AsnNumber FROM @t) as query1
  WHERE AsnNumber = '1777188';

  WITH query1 (AsnNumber) AS 
  (SELECT CAST(CAST(AsnNumber AS BIGINT) AS NVARCHAR(33)) as AsnNumber FROM @t)
  SELECT AsnNumber FROM query1
  WHERE AsnNumber = '1777188';

END

这表明您的查询＃1工作正常，它还演示了我可以将它用作子查询，我可以在公用表表达式中使用它，但仍然没有错误。我不知道你为什么会收到错误。

也许您可以包含一整套语句来创建表，用数据填充它，然后运行产生错误的确切查询？如果你这样做，它将帮助我重现这个问题，然后我可以解释它为什么会发生。目前，我无法重现您的问题。

在SQL Server中将数据类型nvarchar转换为bigint时出错

1 个答案: