存储过程报错！！！怎么写啊
create proc InPutAllowanceCount
 @ExpertName nvarchar(100),
 @TenerCollege nvarchar(100),
 @RetainPost nvarchar(100)

as
  declare @sql varchar(4000) 
  begin 
 
set @sql = 'select ExpertName,AgreementName,TenerCollege,RetainPost,StartRetainDate,EndRetainDate '  
select @sql = @sql + ',sum(case AllowanceTypeName when '''+AllowanceTypeName+''' then AllowanceTotal else 0 end) ['+AllowanceTypeName+']' 
from (select distinct AllowanceTypeName from vwExpertAllowanceCount) as a  
select @sql = @sql+' from vwExpertAllowanceCount where 1=1 '

if( @ExpertName<>'' or @ExpertName is not null)
  @sql = @sql+' and ExpertName='''+@ExpertName+''''

  if( @TenerCollege<>'' or @TenerCollege is not null )
  @sql = @sql+' and TenerCollege='''+@TenerCollege+''''
  if(@TenerCollege<>'' or @RetainPost is not null)
@sql = @sql+' and RetainPost='''+@RetainPost+'''
group by ExpertName,TenerCollege,StartRetainDate,EndRetainDate,AgreementName, RetainPost'
  end 
 exec(@sql)

------解决方案--------------------
这3个错误都是一个问题，Sql Server 对变量赋值需要使用 Set 或者 Select 
具体的报错在如下3句
@sql = @sql+' and ExpertName='''+@ExpertName+''''

@sql = @sql+' and TenerCollege='''+@TenerCollege+'''' 

@sql = @sql+' and RetainPost='''+@RetainPost+''' 

对变量的赋值应该加上
Set 或者 Select 

所以更改为
set @sql = @sql+' and ExpertName='''+@ExpertName+''''

set@sql = @sql+' and TenerCollege='''+@TenerCollege+'''' 

set @sql = @sql+' and RetainPost='''+@RetainPost+''' 

看来我占沙发 并且是正解了