sql – 如何确定哪些字符串或二进制数据将被截断？

我有一个大多数时间都可以运行的存储过程,但是每次都会收到一条错误消息：

Msg 8152,Level 16,State 2,Line 98
String or binary data would be truncated.
The statement has been terminated.

如何确定导致此问题的数据字符串？

解决方法

对于这个能够很好地处理更复杂的选择查询的答案,让我们假设我们有三个表定义如下……

CREATE TABLE [dbo].[Authors](
    [AuthorID] [int] NOT NULL,[AuthorName] [varchar](20) NOT NULL
) ON [PRIMARY]

CREATE TABLE [dbo].[Books](
    [BookID] [int] NOT NULL,[AuthorID] [int] NOT NULL,[BookName] [varchar](20) NOT NULL
) ON [PRIMARY]

CREATE TABLE [dbo].[Publications](
    [BookID] [int] NOT NULL,[PublicationName] [varchar](10) NOT NULL,[WrittenBy] [varchar](10) NOT NULL
) ON [PRIMARY]

…我们创建以下数据……

INSERT INTO Authors ( AuthorID,AuthorName ) VALUES ( 1,'BOB' )
INSERT INTO Authors ( AuthorID,AuthorName ) VALUES ( 2,'JANE' )
INSERT INTO Authors ( AuthorID,AuthorName ) VALUES ( 3,'SOREN LONGNAMESSON' )

INSERT INTO Books ( BookID,AuthorID,BookName ) VALUES ( 1,1,'My Life' )
INSERT INTO Books ( BookID,BookName ) VALUES ( 2,2,'Writing Long Titles For Dummies' )
INSERT INTO Books ( BookID,BookName ) VALUES ( 3,3,'Read Me' )

…而我们抛出错误的复杂查询是……

INSERT INTO Publications SELECT Books.BookID,Books.BookName,Authors.AuthorID,Authors.AuthorName FROM Books JOIN Authors ON Books.AuthorID = Authors.AuthorID

…然后我们可以找到可能像这样冒犯的列……

步骤1
将INSERT语句转换为SELECT INTO语句,并将结果写入临时表,如下所示…

SELECT Books.BookID,Authors.AuthorName INTO ##MyResults FROM Books JOIN Authors ON Books.AuthorID = Authors.AuthorID

第2步
现在执行以下T-SQL,将目标表的列定义与复杂查询的源列进行比较…

SELECT
            SourceColumns.[name] AS SourceColumnName,SourceColumns.[type] AS SourceColumnType,SourceColumns.[length] AS SourceColumnLength,DestinationColumns.[name] AS SourceColumnName,DestinationColumns.[type] AS SourceColumnType,DestinationColumns.[length] AS SourceColumnLength
FROM
            tempdb.sys.syscolumns SourceColumns
JOIN        tempdb.sys.sysobjects SourceTable ON SourceColumns.[id] = SourceTable.[id]
LEFT JOIN   sys.syscolumns DestinationColumns ON SourceColumns.colorder = DestinationColumns.colorder
LEFT JOIN   sys.sysobjects DestinationTable ON DestinationColumns.[id] = DestinationTable.[id]
WHERE
            SourceTable.Name = '##MyResults'
AND         DestinationTable.Name = 'Publications'

您可以调整此查询以过滤到某些列类型(您知道问题是字符串或二进制数据)以及源列的长度大于目标列的位置.有了这些信息,您应该只留下一些可能导致截断的列,并可以从那里开始搜索.

小费！检查您的目标列是否有ON INSERT TRIGGERS！