记一个数据库游标的实例

Posted 2020-10-28 追逐时光者

--数据游标在数据库中起到的就是一个书签的作用，它让一个抽象的成员实例化为一个准确的对象。游标虽好，但是可不能多次使用，运行效率会降低！  

USE [数据库名]
GO

Create procedure [dbo].[proc_gitcontent]//存储过程名称
as

declare --声明变量（用于插入数据）
@content varchar(max),
@sendsuccesscount int,
@sendfailecount int,
@submitfailcount int,
@unknown int,
@status int,
@userid int,
@addtime datetime

--定义一个游标cursor(相当于一个书签)
declare content_cursor cursor for select Content,userid from tbl_sms_log group by Content,userid
declare @sum int
set @sum=0
create table #table
(
[ID] int identity(1,1) primary key NOT NULL,
[Userid] int null,--用户id
[content] [varchar](max) null,--内容
[sendsuccess] [int] null,--发送成功 10
[sendfail] [int] null,--发送失败 20
[submitfail] [int] null,--提交失败 2
[unknown] [int] null,--未知数 0
[addtime] [datetime] null--添加时间
)
--打开游标
open content_cursor


  --读取游标(遍历赋值)(解决重复插入的bug)
   fetch next from content_cursor into @content,@userid
 while @@FETCH_STATUS=0   --返回游标执行状态（0表示返回结果成功）
  begin
   --发送成功赋值
   set @sendsuccesscount=(select COUNT([status]) from tbl_sms_log where status=‘10‘ and Content=@content and UserID=@userid group by Content,userid,[status])
   --发送失败赋值
   set @sendfailecount=(select COUNT([status]) from tbl_sms_log where status=‘20‘ and Content=@content and UserID=@userid group by Content,userid,[status])
   --提交失败赋值
   set @submitfailcount=(select COUNT([status]) from tbl_sms_log where status=‘2‘ and Content=@content and UserID=@userid group by Content,userid,[status])
   --未知赋值
   set @unknown=(select COUNT([status]) from tbl_sms_log where status=‘0‘ and Content=@content and UserID=@userid group by Content,userid,[status])

 set @addtime =GETDATE()
   
   --set @sum+=1
   insert into #table(Userid,content,sendsuccess,sendfail,submitfail,unknown,addtime) values (@userid,@content,@sendsuccesscount,@sendfailecount,@submitfailcount,@unknown,@addtime)

fetch next from content_cursor into @content,@userid--游标再次赋值，解决数据重复插入的bug
   end
--关闭游标（decalre content_cursor cursor for）
close content_cursor

--释放资源
deallocate content_cursor
begin

select * from #table

--关闭游标

end