一个动态SQL问题
declare   @pageSize   int
declare   @fields   varchar(100)
declare   @tbName   varchar(30)
declare   @where   varchar(100)
declare   @pK   varchar(30)
declare   @orderBy   varchar(1000)
declare   @cPage   int
declare   @sql   nvarchar(3000)
set   @pageSize   =   2
set   @fields   =   '[UserID],[UserName] '
set   @tbName   =   '[vsUser] '
set   @where   =   '1=1 '
set   @pK   =   '[UserID] '
set   @orderBy   =   '[UserID]   DESC '
set   @cPage   =   2

set   @sql   =   'SELECT   TOP   '   +   cast(@pageSize   as   varchar(10))+   '   '   +   @fields   +   '   FROM   '   +  
@tbName   +   '   WHERE   '   +   @where   +   '   AND   '   +   @pK   +   '   NOT   IN(SELECT   TOP   '   +  
cast((@cPage-1)*@pageSize   as   varchar(10))+   '   '   +   @pK   +   '   FROM   '   +   @tbName   +   '   WHERE   '   +   @where   +  
'   ORDER   BY   '   +   @orderBy   +   ')   ORDER   BY   '   +   @orderBy   -----> ①

EXEC(@sql)----> ②

这样能正确执行

但如果换成将①②合并,写成Exec( 'SELECT   TOP   '   +   cast(@pageSize   as   varchar(10))+   '   '   +   @fields   +   '   FROM   '   +  
@tbName   +   '   WHERE   '   +   @where   +   '   AND   '   +   @pK   +   '   NOT   IN(SELECT   TOP   '   +  
cast((@cPage-1)*@pageSize   as   varchar(10))+   '   '   +   @pK   +   '   FROM   '   +   @tbName   +   '   WHERE   '   +   @where   +  
'   ORDER   BY   '   +   @orderBy   +   ')   ORDER   BY   '   +   @orderBy)

就提示: 'cast '   附近有语法错误。

请教大虾,这是为什么?

------解决方案--------------------
不能在exec 里写~~cast~~
declare @sql varchar(5000)
set @sql= 'SELECT TOP ' + cast(@pageSize as varchar(10))+ ' ' + @fields + ' FROM ' +
@tbName + ' WHERE ' + @where + ' AND ' + @pK + ' NOT IN(SELECT TOP ' +
cast((@cPage-1)*@pageSize as varchar(10))+ ' ' + @pK + ' FROM ' + @tbName + ' WHERE ' + @where +
' ORDER BY ' + @orderBy + ') ORDER BY ' + @orderBy
Exec(@sql)