怎样在SQL Server中去除表中不可见字符

以下的实例为去除指定表中数据类型是VARCHAR,CHAR,NVARCHAR的字段值中的不可见字符。 注释：此处只去掉前后的不可见字符，不包括中间的字符，而且没有区分中文。

在使用前需要指定对应要修改的表名，并且需要在对应数据库下执行；

SET NOCOUNT ON
DECLARE @TblName  VARCHAR(100)
DECLARE @UpdateString NVARCHAR(1000)
DECLARE @SelectString NVARCHAR(1000)
DECLARE @COlName VARCHAR(100)
DECLARE @COUNT  INT
SET @TblName = 'YOURTABLENAME'--指定想要修改的表名
--定义游标取出指定表内的数据类型是VARCHAR,char,nVARCHAR的字段名称
DECLARE cur_ColName  CURSOR
FOR
SELECT col.name
FROM syscolumns AS col
inner join sysobjects  AS obj  ON col.ID = obj.ID
INNER join systypes  AS typ  ON col.xtype = typ.xtype
WHERE obj.xtype ='U'
AND obj.name = @TblName
AND typ.name IN ('VARCHAR','CHAR','NVARCHAR','NCHAR')
FOR READ ONLY
--打开游标
OPEN cur_ColName
FETCH NEXT FROM cur_ColName INTO @ColName
IF @@FETCH_STATUS<>0
BEGIN
PRINT '没有对应表或字段，
'PRINT '请确认当前数据库内有' + @TblName + '表，
' PRINT '或该表内有VARCHAR、CHAR、NVARCHAR、NCHAR类型的字段！
' GOTO LABCLOSE
END--循环修改
WHILE @@FETCH_STATUS=0
BEGIN
--拼修改字符串
--去掉左边的不可见字符
SET @SelectString = 'SELECT @COU=COUNT(*)    
FROM ' + @TblName +'   
WHERE ASCII(LEFT(' + @ColName +',1))<32
AND '+ @ColName + ' IS NOT NULL'
EXEC sp_executesql @SelectString,N'@COU INT OUTPUT',
@COUNT OUTPUT WHILE @COUNT>0
BEGIN 
SET @UpdateString =  
' UPDATE ' + @TblName +  
' SET ' + @ColName + '=RIGHT(' + @ColName + ',LEN(' + @ColName + ')-1)   
WHERE ASCII(LEFT(' + @ColName + ',1))<32   
AND ' + @ColName + ' IS NOT NULL' 
EXEC sp_executesql @UpdateString 
EXEC sp_executesql @SelectString,N'@COU INT OUTPUT',@COUNT OUTPUT
END
--去掉右边的不可见字符 SET @SelectString = 'SELECT @COU=COUNT(*)    
FROM ' + @TblName +'   
WHERE ASCII(RIGHT(' + @ColName +',1))<32   
AND '+ @ColName + ' IS NOT NULL'
EXEC sp_executesql @SelectString,N'@COU INT OUTPUT',
@COUNT OUTPUT WHILE @COUNT>0
BEGIN 
SET @UpdateString =   ' UPDATE ' + @TblName +   ' SET '
+ @ColName + '=LEFT(' + @ColName + ',LEN(' + @ColName + ')-1)   
WHERE ASCII(RIGHT(' + @ColName + ',1))<32   
AND ' + @ColName + ' IS NOT NULL' 
EXEC SP_EXECUTESQL @UpdateString 
EXEC sp_executesql @SelectString,N'@COU INT OUTPUT',
@COUNT OUTPUT
END
PRINT 'column: ' + @ColName + '－－－ok'
FETCH NEXT FROM cur_ColName INTO @ColName
END
--关闭、释放游标LABCLOSE: CLOSE cur_ColName 
DEALLOCATE cur_ColName