■最近做了三个问题,虽然很小,而且实现的也...... 最近做了三个问题,虽然很小,而且实现的也略显笨拙,但还是想记录下来,供大家参考一下,也满足一下自己的一种虚荣心,呵呵:) 问题一: 要求对一表中的字符数据进行自动编码,基本要求大概是:第一条数据编码为'FM00000',第二条为'FM00001',第三条为"FM00002',以次类推;刚好最近在练习写触发器,简单实现了一下. 实现思路: 建立主键为identity的表,利用表主键的identity属性,在触发器中拼成所需字符串,当向表insert数据时更新相应字段值 --建表 CREATE TABLE [dbo].[test_table] ( [ID] [int] IDENTITY (1, 1) NOT NULL , [NAME] [varchar] (80) ) ON [PRIMARY] GO --建立触发器 CREATE trigger test_trigger on test_table for insert as update test_table set name =substring('FM'+stuff('00000',5-len(i.id)+1,len(i.id),CAST(i.id AS char(5))),1,7) from inserted i where i.id=test_table.id GO --测试插入语句 insert into test_table select 1 union select 2 union select 3 union select 4 union select 5 如不使用identity的字段上面的触发器也可以做修改,如下: alter trigger test_trigger on test_table for insert as declare @next_seq int select @next_seq=(select cast ((select substring(max(name),3,5) from test_table) as int)+1) update test_table set name =substring(stuff('FM00000',7-len(@next_seq)+1,len(@next_seq),cast(@next_seq as char(5))),1,7) --或者如此,这样更简单: -- set name ='FM'+right('00000'+cast(@next_seq as varchar),5) from inserted i where i.id=test_table.id GO 问题二: 查询中实现对价格等货币值格式化为$0,000.00样式的问题,实现如下: 货币转换: select '$'+convert(varchar,cast(tb字段 as money),1) 示例: select '$'+convert(varchar,cast(111111.5 as money),1) 问题三: 编写触发器,对一表中插入的日期数据修改为该日期所处月份的最后一天 脚本如下: --建测试表 create table test_table ( id int IDENTITY(1,1) primary key, mytime datetime NOT NULL) GO --建触发器 create trigger date_change_trigger on test_table for insert as update test_table set mytime = (select dateadd(ms,-3,dateadd(m,datediff(m,0,(select mytime from inserted))+1,0))) from inserted i where test_table.id=i.id GO |
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