触发器中如何对依赖于另一字段的字段进行赋值?

[huazai]

在数据库表中添加一条记录，其中表中的一个字段a为自增字段，另一个字段b的值依赖于前一个字段的值，我想在该表上建立个触发器，当添加记录时，能够把添加记录的b字段的值同时进行更改，请问怎么搞，最好在触发器中，因为很多地方有此操作。

[pengdali]

CREATE TRIGGER 名 on 表
INSTEAD OF INSERT
AS
BEGIN
INSERT 表 (列1,列2,列3) SELECT 列1,列2,列1+列2-100 FROM inserted
END

[愉快的登山者]

create trigger t1 on table1
for insert
as
update table1 set b = a from inserted where table1.id = inserted.id

[愉快的登山者]

create trigger t1 on table1
for insert
as
update table1 set b = a from inserted where table1.a = inserted.a

[woyaofengle]

create trigger t1 on table1
for insert
as
update table1 set b = a+100 from inserted where table1.a = inserted.a

[woyaofengle]

--create table a(CategoryID int identity(1,1),name char(20) null, SubCategory char(10))
--insert into a (name) values('sub11')
--insert into a (name) values('sub12')
--insert into a (name) values('sub13')
--insert into a (name) values('sub14')
--insert into a (name) values('sub21')
--insert into a (name) values('sub22')
go
create trigger t1 on a
instead of insert
as
begin
insert into a (name,SubCategory) select name,cast(CategoryID as char(10))+'wofengle' from inserted
end
--select * from a
--insert into a (name) values('sub23')
--drop trigger t1

[woyaofengle]

--create table a(CategoryID int identity(1,1),name char(20) null, SubCategory char(10))
--insert into a (name) values('sub11')
--insert into a (name) values('sub12')
--insert into a (name) values('sub13')
--insert into a (name) values('sub14')
--insert into a (name) values('sub21')
--insert into a (name) values('sub22')
go
create trigger t1 on a
instead of insert
as
begin
insert into a (name,SubCategory) select name,cast(CategoryID as char(10))+'wofengle' from inserted
end
--select * from a
--insert into a (name) values('sub23')
--drop trigger t1
但执行时有问题，还望大侠们多多指点

[txlicenhe]

CREATE TRIGGER yourTriggerName on yourTable
For INSERT
AS
BEGIN
Update B set yourField = newValue From B join Inserted on B.KeyField = Inserted.KeyField
END

[sdhdy]

create trigger trig_table1_insert on table1
for insert
as
update table1 set b = a from inserted where table1.a = inserted.a