上次的问题还是没解决 麻烦各位路过的好心人指教

if exists(select 1 from sysobjects where id=object_id('sp_watercode'))
drop procedure sp_watercode
go
create procedure sp_watercode @flag varchar(7),
@key varchar(15),
@table varchar(20)
as
declare @watercode varchar(20）

exec('select '+@watercode+'= max(' + @key +') from' + @table
+'where substring('+@key+',len('''+@flag+
'''),8)=convert(varchar(8),getdate(),112)')

if isnull(@watercode,'')=''
select @watercode=@flag+convert(varchar(8),getdate(),112)+'001'
else
select @watercode=@flag+convert(varchar(8),getdate(),112)+
right( '000'+cast(cast(right(@watercode,3) as int)+1 as varchar(3)),3)
这个错在哪里 请人指教啊 我真的等了好久