一：数据库的列为整形是，我们可以使用关键字Identity(1,1)实现
二:数据库的列为字符串varchar时，我们仍可实现自增长
create table test001(id nvarchar(10),content varchar(10))go--创建触发器create trigger tg_test001on test001instead of insertasdeclare @content nvarchar(10)select @content= content from insertedinsert into test001(id,content)select cast(isnull(max(id),'0') as int)+1,@contentfrom test001 go--向表中插入数据insert into test001 (content) select 'a'insert into test001 (content) select 'b'go--选择察看插入效果select * from test001go