关于组合查询字符串与重复记录的删除

declare @i int,@sql nvarchar(1000)
set @i=1
while @i<=7
begin
select @sql='update itairc set com'+cast(@i as varchar)+'=replace(com'+cast(@i as varchar)+',''<NOBR>'','''')'
EXEC sp_executesql @sql
set @i=@i+1
end

delete weitran_emailbook where id in (select max(id) from weitran_emailbook  group by email_address having count(*)>1)