讨论一下触发器

[wolflove23]

create trigger tri_a on a
for insert
as
begin
declare @name varchar(50)
select @name=name from inserted
if not exists(select name from b where name=@name)
insert b(name)select name from inserted
end
go
上面语句的意思是当向a表插入数据name时，如果b表中没有这个name 那么就把name插入到b表。b表name列是主键。
谁能写得更简洁一些。

[wolflove23]

表a
name
a
b
a
c
c
表b
name
a
b
c
如果表a中的c全部删除时，就把表b中的c 删除掉，怎么做？

[areswang]

create trigger test on a
for delete
as
delete b where not exists(select 1 from a where a.name = b.name )
go

[昵称被占用了]

如果表a中的c全部删除时，就把表b中的c 删除掉，怎么做？

create trigger tri_a_delete on a  
for delete
as 
  delete b 
  from deleted d,b
  where d.name=b.name
  and not exists (
    select 1 from a
    where name=d.name
    )
go 

[昵称被占用了]

问题不是简洁的问题，而是正确性的问题

create     trigger       tri_a       on     a   
for       insert 
as   
  insert   b(name)
  select   name   from   inserted i
  where not   exists(select   1   from   b   where   name=i.name)
go 

[tim_spac]

create trigger tri_a on a  
for insert
as begin
  insert into b 
  select name 
  from inserted i 
  where not exists (
    select 1 from b
    where b.name=i.name)
end
go