我想用触发器实现一个类型日志的功能。其思想是取一个表的所有的字段名,然后遍历这个字段名,在inserted表deleted表中分别取修改前后的值,比较是否一样再进行处理。问题是我现在通过如下的语句只能取到字段名,而取不到该字段的值。
比如下两句
select @c1=@s from inserted
select @c2=IQ_OtherName from deleted@c1只能取到字段名,第二句IQ_OtherName中数据表中实际的列名,能取到值。set ANSI_NULLS ON
set QUOTED_IDENTIFIER ON
goALTER TRIGGER [DbLog] ON [dbo].[En_Cus_Inquiry_bak20080523]
FOR INSERT,UPDATE
AS
begin
declare @s nvarchar(4000)
declare @HSCode nvarchar(200)
declare colName cursor local for
select name from syscolumns where id=(select max(id) from sysobjects where xtype='u' and name='En_Cus_Inquiry_bak20080523')
open colName
fetch colName into @s
while @@fetch_status=0
begin
declare @c1 nvarchar(50)
declare @c2 nvarchar(50)
declare @sql1 nvarchar(50)
select @c1=@s from inserted
select @c2=IQ_OtherName from deleted
print @c1
print @c2
fetch colName into @s
end
close colName
deallocate colName
end
比如下两句
select @c1=@s from inserted
select @c2=IQ_OtherName from deleted@c1只能取到字段名,第二句IQ_OtherName中数据表中实际的列名,能取到值。set ANSI_NULLS ON
set QUOTED_IDENTIFIER ON
goALTER TRIGGER [DbLog] ON [dbo].[En_Cus_Inquiry_bak20080523]
FOR INSERT,UPDATE
AS
begin
declare @s nvarchar(4000)
declare @HSCode nvarchar(200)
declare colName cursor local for
select name from syscolumns where id=(select max(id) from sysobjects where xtype='u' and name='En_Cus_Inquiry_bak20080523')
open colName
fetch colName into @s
while @@fetch_status=0
begin
declare @c1 nvarchar(50)
declare @c2 nvarchar(50)
declare @sql1 nvarchar(50)
select @c1=@s from inserted
select @c2=IQ_OtherName from deleted
print @c1
print @c2
fetch colName into @s
end
close colName
deallocate colName
end
1 :普通SQL语句可以用Exec执行 eg: Select * from tableName
Exec('select * from tableName')
Exec sp_executesql N'select * from tableName' -- 请注意字符串前一定要加N 2:字段名,表名,数据库名之类作为变量时,必须用动态SQL eg:
declare @fname varchar(20)
set @fname = 'FiledName'
Select @fname from tableName -- 错误,不会提示错误,但结果为固定值FiledName,并非所要。
Exec('select ' + @fname + ' from tableName') -- 请注意 加号前后的 单引号的边上加空格 当然将字符串改成变量的形式也可
declare @fname varchar(20)
set @fname = 'FiledName' --设置字段名 declare @s varchar(1000)
set @s = 'select ' + @fname + ' from tableName'
Exec(@s) -- 成功
exec sp_executesql @s -- 此句会报错 declare @s Nvarchar(1000) -- 注意此处改为nvarchar(1000)
set @s = 'select ' + @fname + ' from tableName'
Exec(@s) -- 成功
exec sp_executesql @s -- 此句正确 3. 输出参数
declare @num int,
@sqls nvarchar(4000)
set @sqls='select count(*) from tableName'
exec(@sqls)
--如何将exec执行结果放入变量中? declare @num int,
@sqls nvarchar(4000)
set @sqls='select @a=count(*) from tableName '
exec sp_executesql @sqls,N'@a int output',@num output
select @num
对象名 'inserted' 无效。
set @sql1= 'select ' + @s + ' from inserted'
exec(@sql1)
exec(@sql1)
--exec(@sql1)
print @sql1你把语句打印出来,看看是什么语法错误,是不是少了空格什么的
我要是把inserted换成实际的表,在查询分析器中改为如下形式是没问题的.
USE sunivoWeb
GO
select IQ_PrePayTerms from En_Cus_Inquiry_bak20080523
不知道这是不是必须要换行才能运行