Sql more difficult problems in the forum: 9 (insert topic trigger automatic data update table data)

Original: more difficult problems in sql forum: 9 (insert topic trigger automatic data update table data)

Recently, in the forum, I met a lot more difficult sql problem, although they can be resolved, but found a few days later, they can not remember, forget the solution of.

So, I feel the need to be recorded, so that after the encounter this problem again, and get answers from the idea.

Trigger problem, insert the data, automatically updating data table

http://bbs.csdn.net/topics/390634682

Table 1 has a field 1, field 2
is inserted into data of 4 rows
Field 1 Field 2
101
102
101
102
I want to trigger, direct update field 2, to achieve
Field 1 Field 2
101 101 + 1
102 102 + 1
101 + 101 2
102 2 102 +
this function, please help us to see how to achieve,

When inserting data, to achieve the update.

1, for 2005 and later:

   
   
--drop table tb

create table tb
(字段 1 int, 字段 2 int, 字段 3 int, 字段 4 int)


drop trigger trigger_tb

create trigger dbo.trigger_tb
on tb
for insert
as

;with t
as
(
select tb.*,
row_number() over( partition by tb.字段 1 order by tb.字段 4) as rownum
from tb
inner join inserted i
on tb.字段 1 = i.字段 1
and tb.字段 3 = i.字段 3
and tb.字段 4 = i.字段 4
)

update t
set 字段 2 = 字段 1+ rownum

go


insert into tb
select 101, null, 1, 1
union all select 102, null, 1, 2
union all select 101, null, 1, 3
union all select 102, null, 1, 4


--查询
select *
from tb
/*
字段1 字段2 字段3 字段4
101 102 1 1
102 103 1 2
101 103 1 3
102 104 1 4
*/
  
  

Method 2 for 2000:

   
   
--drop table tb

create table tb
(字段 1 int, 字段 2 int, 字段 3 int, 字段 4 int)


--drop trigger trigger_tb

create trigger dbo.trigger_tb
on tb
for insert
as

update tb
set 字段 2 = t1.字段 1 + ( select count(*) from tb t2
where t2.字段 1 = t1.字段 1
and t2.字段 4 <= t1.字段 4)
from tb t1
inner join inserted i
on t1.字段 1 = i.字段 1
and t1.字段 3 = i.字段 3
and t1.字段 4 = i.字段 4

go


insert into tb
select 101, null, 1, 1
union all select 102, null, 1, 2
union all select 101, null, 1, 3
union all select 102, null, 1, 4


--查询
select *
from tb
/*
字段1 字段2 字段3 字段4
101 102 1 1
102 103 1 2
101 103 1 3
102 104 1 4
*/
  
  

As another example, SQL Server2000 update a table of the flip-flop to achieve:

   
   
--drop table mocta

create table purtb
(请购单号 varchar( 10),参考单号 varchar( 10),备注 varchar( 50))

create table mocta
(工单单号 varchar( 10),订单单号 varchar( 10))


insert into purtb
select '101', '201', '301' union all
select '102', '302', '302' union all
select '103', '备料', '备料'

insert into mocta
select '201', '301' union all
select '202', '302'
go

--drop trigger trigger_purtb_insert



create trigger dbo.trigger_purtb_insert
on purtb
for insert
as

update purtb
set 备注 = isnull(( select t1.订单单号
from mocta t1
where i.参考单号 = t1.工单单号),
i.参考单号)
from inserted i
where purtb.请购单号 = i.请购单号 and
purtb.参考单号 = i.参考单号


go


insert into purtb(请购单号,参考单号)
select '104', '201'
union all select '105', 'xxx'




--查询
select *
from purtb
/*
请购单号 参考单号 备注
101 201 301
102 302 301
103 备料 备料
104 201 301
105 xxx xxx
*/